Semiconductor devices having isolation insulating layers and methods of manufacturing the same

ABSTRACT

The inventive concepts provide semiconductor devices and methods of manufacturing the same. Semiconductor devices of the inventive concepts may include a fin region comprising a first fin subregion and a second fin subregion separated and isolated from each other by an isolation insulating layer disposed therebetween, a first gate intersecting the first fin subregion, a second gate intersecting the second fin subregion, and a third gate intersecting the isolation insulating layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patent application Ser. No. 14/600,689, filed on Jan. 20, 2015, which claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2014-0010202 filed on Jan. 28, 2014 and Korean Patent Application No. 10-2014-0031713 filed on Mar. 18, 2014, the disclosures of which are hereby incorporated by reference in their entirety.

FIELD

The inventive concepts relate to semiconductor devices and methods of manufacturing the same and, more particularly, to semiconductor devices having a three-dimensional channel and methods of manufacturing the same.

BACKGROUND

As semiconductor devices have become more highly integrated, the integration density of semiconductor devices has progressively increased. Because integration density is limited by the area of the device and the ability to form patterns within that area, there is a need for new methods that are capable of producing finer, more precise patterns than are possible using conventional techniques.

Fin field effect transistors (FINFETs) have been developed as one means of increasing the integration density of semiconductor devices. As sizes of FINFET devices have been reduced to 20 nm or less, it has become increasingly difficult to form isolation insulating layers in fin regions using conventional patterning methods, such as those discussed in U.S. Patent Publication No. 2013/0187237.

The inventive concepts provide structures and methods for producing finer, more precise patterns by preventing the misalignment of photolithography processes and insulating fin regions from each other in a lateral direction.

SUMMARY

The inventive concepts provide semiconductor devices having an isolation insulating layer that is self-alignedly formed to separate fin regions from each other. Such devices may exhibit improved reliability by preventing a short or leakage current between a gate electrode disposed on an isolation insulating layer and a source/drain region.

In some embodiments, semiconductor devices of the inventive concepts comprise a substrate; a fin region disposed on the substrate, the fin region comprising a first fin subregion and a second fin subregion spaced apart from each other in a first direction on the substrate; a discrete isolation insulating island disposed between the first fin subregion and the second fin subregion to separate the first fin subregion from the second fin subregion; a first gate intersecting the first fin subregion and extending in a second direction different from the first direction; a second gate intersecting the second fin subregion and extending in the second direction; and a third gate intersecting the discrete isolation insulating island, extending in the second direction and covering at least a sidewall of the discrete isolation insulating island. Each of the first, second and third gates may include a gate dielectric layer and a gate electrode.

In some embodiments, semiconductor devices of the inventive concepts comprise a substrate; a fin region including a first fin subregion and a second fin subregion spaced apart from each other in a first direction on the substrate, the fin region extending in the first direction; a first gate intersecting the first fin subregion in a second direction different from the first direction; a second gate intersecting the second fin subregion in the second direction; a first isolation insulating layer having a liner-shape formed on a sidewall of a recess region provided in the fin region between the first gate and the second gate; and a third gate covering the first isolation insulating layer and extending in the second direction. Each of the first, second and third gates may include a gate dielectric layer and a gate electrode.

In some embodiments, semiconductor devices of the inventive concepts comprise a substrate; a plurality of fin regions disposed on the substrate and spaced apart from each other in a second direction, each of the fin regions comprising a first fin subregion and a second fin subregion spaced apart from each other in a first direction different from the second direction; a plurality of discrete isolation insulating islands spaced apart from each other in the first direction and second direction, each of the discrete isolation insulating islands disposed in one of the plurality of fin regions between the first fin subregion and second fin subregion to separate the first fin subregion from the second fin subregion; a first source/drain region formed in the first fin subregion of each of the fin regions; a second source/drain region formed in the second fin subregion of each of the fin regions; a punch-through stop layer disposed underneath each of the discrete isolation insulating islands, a conductivity type of the punch-through stop layer being different from that of the first and second source/drain regions; a first gate intersecting the first fin subregion in each of the plurality of fin regions; a second gate intersecting the second fin subregion in each of the plurality of fin regions; and a third gate intersecting the discrete isolation insulating island in each of the plurality of fin regions.

The inventive concepts also provide methods of manufacturing a semiconductor device that comprises an isolation insulating layer that is self-alignedly formed to isolate fin regions from each other. Such methods may be used to fabricate semiconductor devices having improved reliability by preventing a short or leakage current between a gate electrode disposed on an isolation insulating layer and a source/drain region. In some embodiments, methods of the inventive concepts comprise forming a fin region extending in a first direction on a substrate; forming a discrete isolation insulating island comprising an oxide layer in the fin region by oxidizing a portion of the fin region, thereby forming a first fin subregion and a second fin subregion separated from each other in the first direction by the discrete isolation insulating island; and forming a third gate covering at least a sidewall of the discrete isolation insulating island, the third gate extending in a second direction different from the first direction.

In some embodiments, methods of the inventive concepts comprise forming a first fin subregion and a second fin subregion spaced apart from each other in a first direction on a substrate; forming a first discrete isolation insulating island disposed between the first fin subregion and the second fin subregion, the discrete isolation insulating island separating the first fin subregion from the second fin subregion; forming a first gate intersecting the first fin subregion and extending in a second direction different from the first direction; forming a second gate intersecting the second fin subregion and extending in the second direction; and forming a third gate covering a top surface and sidewalls of the discrete isolation insulating island and extending in the second direction. Each of the first to third gates may include a gate dielectric layer and a gate electrode.

In some embodiments, methods of the inventive concepts comprise forming a fin region extending in a first direction on a substrate; forming gate spacers on the fin region, the gate spacers extending in a second direction different from the first direction, and a groove defining that exposes a portion of the fin region; removing the portion of the fin region exposed by the groove to form a recess region; oxidizing the surfaces of the recess region to form an oxide layer; forming a filling insulation layer filling the recess region on the oxide layer to form a isolation insulating layer comprising the oxide layer and the filling insulation layer; and forming a gate filling the groove on the filling insulation layer, the gate including a gate dielectric layer and a gate electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects, features and advantages of the inventive concepts will be apparent from the following detailed description of example embodiments of the inventive concepts, as illustrated in the accompanying drawings, in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the inventive concepts. In the drawings:

FIG. 1 is a plan view illustrating semiconductor devices according to embodiments of the inventive concepts;

FIGS. 2A to 2D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate semiconductor devices according to a first embodiment of the inventive concepts;

FIGS. 3A to 3D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate semiconductor devices according to a second embodiment of the inventive concepts;

FIG. 4A is a plan view illustrating semiconductor devices according to a third embodiment of the inventive concepts;

FIGS. 4B to 4E are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 4A, respectively, to illustrate semiconductor devices according to the third embodiment of the inventive concepts;

FIG. 5 is a plan view illustrating semiconductor devices according to embodiments of the inventive concepts;

FIGS. 6A to 6D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 5, respectively, to illustrate semiconductor devices according to a fourth embodiment of the inventive concepts;

FIGS. 7A to 7D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 5, respectively, to illustrate semiconductor devices according to a fifth embodiment of the inventive concepts;

FIGS. 8AA to 8MA are cross-sectional views taken along line A-A′ of FIG. 1, which illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 8AB to 8MB are cross-sectional views taken along line B-B′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 8AC to 8MC are cross-sectional views taken along line C-C′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 8AD to 8MD are cross-sectional views taken along line D-D′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 9A to 9D are cross-sectional views respectively taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 10AA and 10BA are cross-sectional views taken along line A-A′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 10AB and 10BB are cross-sectional views taken along line B-B′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 10AC and 10BC are cross-sectional views taken along line C-C′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 10AD and 10BD are cross-sectional views taken along line D-D′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the first embodiment of the inventive concepts;

FIGS. 11AA and 11BA are cross-sectional views taken along line A-A′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the second embodiment of the inventive concepts;

FIGS. 11AB and 11BB are cross-sectional views taken along line B-B′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the second embodiment of the inventive concepts;

FIGS. 11AC and 11BC are cross-sectional views taken along line C-C′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the second embodiment of the inventive concepts;

FIGS. 11AD and 11BD are cross-sectional views taken along line D-D′ of FIG. 1 to illustrate a method of manufacturing a semiconductor device according to the second embodiment of the inventive concepts;

FIGS. 12AA to 12DA are cross-sectional views taken along line A-A′ of FIG. 4A to illustrate a method of manufacturing a semiconductor device according to the third embodiment of the inventive concepts;

FIGS. 12AB to 12DB are cross-sectional views taken along line B-B′ of FIG. 4A to illustrate a method of manufacturing a semiconductor device according to the third embodiment of the inventive concepts;

FIGS. 12AC to 12DC are cross-sectional views taken along line C-C′ of FIG. 4A to illustrate a method of manufacturing a semiconductor device according to the third embodiment of the inventive concepts;

FIGS. 12AD to 12DD are cross-sectional views taken along line D-D′ of FIG. 4A to illustrate a method of manufacturing a semiconductor device according to the third embodiment of the inventive concepts;

FIGS. 13AA to 13DA are cross-sectional views taken along line A-A′ of FIG. 5 to illustrate a method of manufacturing a semiconductor device according to the fourth embodiment of the inventive concepts;

FIGS. 13AB to 13DB are cross-sectional views taken along line B-B′ of FIG. 5 to illustrate a method of manufacturing a semiconductor device according to the fourth embodiment of the inventive concepts;

FIGS. 13AC to 13DC are cross-sectional views taken along line C-C′ of FIG. 5 to illustrate a method of manufacturing a semiconductor device according to the fourth embodiment of the inventive concepts;

FIGS. 13AD to 13DD are cross-sectional views taken along line D-D′ of FIG. 5 to illustrate a method of manufacturing a semiconductor device according to the fourth embodiment of the inventive concepts;

FIGS. 14AA to 14CA are cross-sectional views taken along line A-A of FIG. 5 to illustrate a method of manufacturing a semiconductor device according to the fifth embodiment of the inventive concepts;

FIGS. 14AB to 14CB are cross-sectional views taken along line B-B′ of FIG. 5 to illustrate a method of manufacturing a semiconductor device according to the fifth embodiment of the inventive concepts;

FIGS. 14AC to 14CC are cross-sectional views taken along line C-C′ of FIG. 5 to illustrate a method of manufacturing a semiconductor device according to the fifth embodiment of the inventive concepts;

FIGS. 14AD to 14CD are cross-sectional views taken along line D-D′ of FIG. 5 to illustrate a method of manufacturing a semiconductor device according to the fifth embodiment of the inventive concepts;

FIG. 15A is a plan view illustrating semiconductor devices according to a sixth embodiment of the inventive concepts;

FIGS. 15B, 15C, 15D, and 15E are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 15A, respectively;

FIG. 16A is a plan view illustrating semiconductor devices according to a seventh embodiment of the inventive concepts;

FIGS. 16B, 16C, 16D, and 16E are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 16A, respectively;

FIG. 17A is a plan view illustrating semiconductor devices according to an eighth embodiment of the inventive concepts;

FIGS. 17B, 17C, 17D, and 17E are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 17A, respectively;

FIGS. 18AA to 18LA are cross-sectional views taken along line A-A′ of FIG. 15A to illustrate a method of manufacturing a semiconductor device according to the sixth embodiment of the inventive concepts;

FIGS. 18AB to 18LB are cross-sectional views taken along line B-B′ of FIG. 15A to illustrate a method of manufacturing a semiconductor device according to the sixth embodiment of the inventive concepts;

FIGS. 18AC to 18LC are cross-sectional views taken along line C-C′ of FIG. 15A to illustrate a method of manufacturing a semiconductor device according to the sixth embodiment of the inventive concepts;

FIGS. 18AD to 18LD are cross-sectional views taken along line D-D′ of FIG. 15A to illustrate a method of manufacturing a semiconductor device according to the sixth embodiment of the inventive concepts;

FIGS. 19AA to 19DA are cross-sectional views taken along line A-N of FIG. 16A to illustrate a method of manufacturing a semiconductor device according to the seventh embodiment of the inventive concepts;

FIGS. 19AB to 19DB are cross-sectional views taken along line B-B′ of FIG. 16A to illustrate a method of manufacturing a semiconductor device according to the seventh embodiment of the inventive concepts;

FIGS. 19AC to 19DC are cross-sectional views taken along line C-C′ of FIG. 16A to illustrate a method of manufacturing a semiconductor device according to the seventh embodiment of the inventive concepts;

FIGS. 19AD to 19DD are cross-sectional views taken along line D-D′ of FIG. 16A to illustrate a method of manufacturing a semiconductor device according to the seventh embodiment of the inventive concepts;

FIGS. 20AA to 20CA are cross-sectional views taken along line A-A′ of FIG. 17A to illustrate a method of manufacturing a semiconductor device according to the eighth embodiment of the inventive concepts;

FIGS. 20AB to 20CB are cross-sectional views taken along line B-B′ of FIG. 17A to illustrate a method of manufacturing a semiconductor device according to the eighth embodiment of the inventive concepts;

FIGS. 20AC to 20CC are cross-sectional views taken along line C-C′ of FIG. 17A to illustrate a method of manufacturing a semiconductor device according to the eighth embodiment of the inventive concepts;

FIGS. 20AD to 20CD are cross-sectional views taken along line D-D′ of FIG. 17A to illustrate a method of manufacturing a semiconductor device according to the eighth embodiment of the inventive concepts;

FIGS. 21A to 21D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 17A, respectively, to illustrate a method of manufacturing a semiconductor device according to the eighth embodiment of the inventive concepts; and

FIG. 22 is a schematic block diagram illustrating an electronic system according to embodiments of the inventive concepts.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of the inventive concepts are shown and in which aspects of the inventive concepts may be exaggerated for clarity. Advantages and features of the inventive concepts and methods of achieving them will be apparent from the following example embodiments, which will be described with reference to the accompanying drawings. The inventive concepts are not limited to the following example embodiments and may be implemented in various forms. The example embodiments are provided only to disclose the inventive concepts and to allow those skilled in the art to more fully understand advantages and features of the inventive concepts. The inventive concepts are not limited to the specific examples provided herein.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the inventive concepts. As used herein, the singular terms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element or intervening elements may be present.

Similarly, it will be understood that when an element such as a layer, region or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present. In contrast, the term “directly” means that there are no intervening elements. It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Additionally, the embodiment in the detailed description will be described with sectional views as ideal example views of the inventive concepts. Accordingly, shapes of the example views may be modified according to manufacturing techniques and/or allowable errors. The inventive concepts are not limited to the specific shape illustrated in the example views, but may include other shapes that may be created according to manufacturing processes. Areas exemplified in the drawings have general properties, and are used to illustrate specific shapes of elements. The drawings should not be construed as limiting the scope of the inventive concept.

It will also be understood that, although the terms first, second, third etc. may be used herein to describe various elements, the elements described thusly should not be limited by those terms. Those terms are only used to distinguish one element from another element. Thus, a first element in some embodiments could be termed a second element in other embodiments without departing from the teachings of the present inventive concepts. Example embodiments of aspects of the inventive concepts explained and illustrated herein include their complementary counterparts. The same reference numerals or the same reference designators denote the same elements throughout the specification.

Moreover, example embodiments are described herein with reference to cross-sectional illustrations and/or plane illustrations that are idealized example illustrations. Accordingly, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, the inventive concepts should not be construed as limited to the shapes of regions illustrated herein; it includes deviations in shapes that result, for example, from manufacturing. For example, a region illustrated as a rectangle may have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the inventive concepts.

As appreciated by the present inventive entity, devices and methods of forming devices according to various embodiments described herein may be embodied in microelectronic devices such as integrated circuits, wherein a plurality of devices according to various embodiments described herein are integrated in the same microelectronic device. Accordingly, the cross-sectional view(s) illustrated herein may be replicated in two different directions, which need not be orthogonal, in the microelectronic device. Thus, a plan view of the microelectronic device that embodies devices according to one or more of the embodiments described herein may include a plurality of the devices in an array and/or in a two-dimensional pattern that is based on the functionality of the microelectronic device.

Devices according to various embodiments described herein may be interspersed among other devices depending on the functionality of the microelectronic device. Moreover, microelectronic devices according to various embodiments described herein may be replicated in a third direction that may be orthogonal to the two different directions, to provide three-dimensional integrated circuits.

Accordingly, the cross-sectional view(s) illustrated herein provide support for a plurality of devices according to various embodiments described herein that extend along two different directions in a plan view and/or in three different directions in a perspective view. For example, when a single active region is illustrated in a cross-sectional view of a device/structure, the device/structure may include a plurality of active regions and transistor structures (or memory cell structures, gate structures, etc., as appropriate to the case) thereon, as would be illustrated by a plan view of the device/structure.

FIG. 1 is a plan view illustrating semiconductor devices according to embodiments of the inventive concepts. FIGS. 2A, 2B, 2C, and 2D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate semiconductor devices according to a first embodiment of the inventive concepts. FIGS. 3A, 3B, 3C, and 3D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate semiconductor devices according to a second embodiment of the inventive concepts.

As shown in FIGS. 1 to 3D, semiconductor devices of the inventive concepts may comprise a substrate 10, a plurality of fin regions 20, a first gate 90 a, a second gate 90 b, a third gate 90 c, a first isolation insulating layer 24, a second isolation insulating layer 60, a first source/drain region 40 a, and a second source/drain region 40 b.

Semiconductor devices of the inventive concepts may comprise any suitable substrate 10. In some embodiments, the substrate 10 is a semiconductor substrate comprising one or more semiconductor materials, such as silicon (Si), germanium (Ge), silicon-germanium (SiGe), gallium-phosphorus (GaP), gallium-arsenic (GaAs), silicon-carbon (SiC), silicon-germanium-carbon (SiGeC), indium-arsenic (InAs), and/or indium-phosphorus (InP).

Fin regions 20 of the inventive concepts may comprise a portion of the substrate 10 and/or an epitaxial layer on the substrate 10. In some embodiments, one or more of the fin regions 20 is an active region vertically protruding from the substrate 10.

Fin regions 20 of the inventive concepts may extend in a first direction X (e.g., an X-axis direction) and may include a first fin subregion 20 a, a second fin subregion 20 b, and a third fin subregion 20 c therebetween in the first direction X. The fin regions 20 may be isolated from each other in a second direction Y (e.g., a Y-axis direction) different from the first direction X by a first isolation insulating layer 24 extending along the first direction X.

Although FIGS. 1 to 3D show two fin regions 20 isolated from each other in the second direction Y, it is to be understood that the inventive concepts are not limited to such embodiments. In some embodiments, three or more fin regions 20 may be present and isolated from each other.

The first direction X and the second direction Y may intersect each other at any suitable angle. In some embodiments, the first direction X and the second direction Y are perpendicular to each other. It is to be understood, however, that the inventive concepts are not limited to such embodiments.

The first direction X may be parallel to a length direction of one or more of the fin regions 20 (e.g., the long axis of each fin region 20), and the second direction Y may be parallel to a width direction of one or more of the fin regions 20 (e.g., the short axis of each fin region 20). Thus, in some embodiments, the ends of the first fin subregions 20 a may face the ends of the second fin subregions 20 b in the first direction X.

The first and second fin subregions 20 a, 20 b may be used as foundations of active regions and/or channel regions of fin field effect transistors (FINFET). In some embodiments, an N-type transistor (e.g., an NMOS transistor) or a P-type transistor (e.g., PMOS transistor) is formed on the first fin subregion 20 a and/or the second fin subregion 20 b. For example, as shown in FIGS. 1 to 3D, a first transistor 110 comprising a first gate 90 a and first source/drain regions 40 a may be formed on the first fin subregion 20 a, and a second transistor 120 comprising a second gate 90 b and second source/drain regions 40 b may be formed on the second fin subregion 20 b. The first transistor 110 and the second transistor 120 may be isolated from each other by the second isolation insulating layer 60.

The first isolation insulating layer 24, which has a height h1, may be disposed directly on the substrate 10 and may be in contact with a sidewall of one or more of the fin regions 20. In some embodiments, the

The first isolation insulating layer 24 may comprise any suitable material(s), including, but not limited to, oxide, nitride, oxynitride, and low-k dielectric material.

The second isolation insulating layer 60 may be disposed between the first fin subregion 20 a and the second fin subregion 20 b (e.g., in the third fin subregion 20 c) to separate the first fin subregion 20 a from the second fin subregion 20 b and to isolate the first source/drain region 40 a from the second source/drain region 40 b in the first direction X. Portions of the first isolation insulating layer 24 may be in direct contact with the second isolation insulating layer 60.

The second isolation insulating layer 60 may comprise a plurality of discrete isolation insulating islands. For example, the second isolation insulating layer 60 may comprise a plurality of discrete isolation insulating islands spaced apart from each other in the first direction X and the second direction Y and aligned with each other in the first direction X.

The second isolation insulating layer 60 may comprise any suitable material(s), including, but not limited to, oxide layers formed by oxidizing a portion of the fin region 20. For example, a portion of the fin region 20 that protrudes upward from the first isolation insulating layer 24 may be oxidized to self-alignedly form the second isolation insulating layer 60. In some embodiments, the second isolation insulating layer 60 is formed in a pillar region 22 located above a plane (shown as a dashed line in FIGS. 2A, 2C, 3A, and 3D) that is coplanar or substantially coplanar with the top surface of the first isolation insulating layer 24. Portions of the top surface of the second isolation insulating layer 60 may be curved. A bottom surface of the second isolation insulating layer 60 may be coplanar or substantially coplanar with or lower than the uppermost surface of the first isolation insulating layer 24 (as shown in FIGS. 2A to 2D) or lower than the uppermost surface of the first isolation insulating layer 24 (as shown in FIGS. 3A to 3D). The top surface of the second isolation insulating layer 60 may be coplanar or substantially coplanar with or lower than the top surfaces of the first and second fin subregions 20 a, 20 b. Sidewalls of the second isolation insulating layer 60 may be in contact with one or more sidewalls of the first fin subregion 20 a and/or one or more sidewalls of the second fin subregion 20 b, respectively. A width of the second isolation insulating layer 60 may be substantially equal to the width(s) of the fin regions 20 in the second direction Y. However, the inventive concepts are not limited thereto. In some embodiments, the width of the second isolation insulating layer 60 may be smaller or larger than the width(s) of the first and second fin subregions 20 a, 20 b. A portion of the third fin subregion 20 c may be disposed underneath the second isolation insulating layer 60. The third fin subregion 20 c may comprise a portion of the fin region 20.

A punch-through stop layer 54 may be formed in the third fin subregion 20 c underneath the second isolation insulating layer 60. The punch-through stop layer 54 may extend into the first fin subregion 20 a and/or the second fin subregion 20 b. The punch-through stop layer 54 may include a high-concentration dopant region. The punch-through stop layer 54 may impede/prevent a leakage current between the first fin subregion 20 a and second fin subregion 20 b (e.g., a leakage current caused by a punch-through phenomenon between the first and second transistors 110 and 120 formed in/on the first and second fin subregions 20 a, 20 b). In some embodiments, the punch-through stop layer 54 may block a leakage current between the first and second fin subregions 20 a, 20 b by impeding/preventing a punch-through phenomenon between a first source/drain region 40 a formed in the first fin subregion 20 a and a second source/drain region 40 b formed in the second fin subregion 20 b.

The punch-through stop layer 54 may have a conductivity type that is different from that of the first and second source/drain regions 40 a, 40 b. In some embodiments, the punch-through stop layer 54 comprises one or more dopants, the conductivity type of which is different from that of the dopant(s) in the first and second source/drain regions 40 a, 40 b. For example, if the first and second source/drain regions 40 a, 40 b include N-type dopants, the punch-through stop layer 54 may include one or more P-type dopants (e.g., boron (B) and/or indium (In)). Alternatively, if the first and second source/drain regions 40 a, 40 b include P-type dopants, the punch-through stop layer 54 may include one or more N-type dopants (e.g., phosphorus (P), arsenic (As), and/or strontium (Sr)).

The punch-through stop layer 54 may have any suitable dopant concentration. In some embodiments, the punch-through stop layer 54 has a dopant concentration in a range of about 10¹⁰ atoms/cm³ to about 10²⁵ atoms/cm³ (e.g., about 10¹⁵ atoms/cm³ to about 10²⁰ atoms/cm³). For example, in some embodiments, the punch-through stop layer 54 may comprise B, BF₂, In, As, P, and/or Sr ion-implanted in a dose of about 10¹¹ atoms/cm² to about 10¹⁵ atoms/cm².

In some embodiments, the punch-through stop layer 54 is not formed.

The first gate 90 a may extend in the second direction Y and may cross over one or more of the first fin subregions 20 a and one or more portions of the first isolation insulating layer 24. In some embodiments, the first gate 90 a covers at least a portion of the top surface of each first fin subregion 20 a disposed thereunder (e.g., a portion of the top surface of the first fin subregion 20 a that is exposed between gate spacers 34 disposed on the top surface of the first fin subregion 20 a). In some embodiments, the first gate 90 a covers a portion of one or more sidewalls of each first fin subregion 20 a disposed thereunder.

The second gate 90 b may extend in the second direction Y and may cross over one or more of the second fin subregions 20 b and one or more portions of the first isolation insulating layer 24. In some embodiments, the second gate 90 b covers at least a portion of the top surface of each second fin subregion 20 b disposed thereunder (e.g., a portion of the top surface of the second fin subregion 20 b that is exposed between gate spacers 34 disposed on the top surface of the second fin subregion 20 b). In some embodiments, the second gate 90 b covers a portion of one or more sidewalls of each second fin subregion 20 b disposed thereunder. The width(s) of the second gate 90 b may be substantially equal to the width(s) of the first gate 90 a.

The third gate 90 c covers at least a portion of the top surface of each second isolation insulating layer 60 disposed thereunder (e.g., portions of the top surface of the second isolation insulating layer 60 that are exposed between gate spacers 34 disposed on the top surfaces of the second isolation insulating layer 60). In some embodiments, the third gate 90 c covers a portion of one or more sidewalls of each second isolation insulating layer 60 disposed thereunder. The width(s) of the third gate(s) 90 c may be substantially equal to or smaller than the width(s) of the first and second gates 90 a, 90 b.

Although FIGS. 1 to 3D show a single third gate 90 c disposed on a single second isolation insulating layer 60, it is to be understood that the inventive concepts are not limited to such embodiments. In some embodiments, two or more third gates 90 c may be disposed on a single second isolation insulating layer 60. Likewise, one or more third gates 90 c may be disposed on each of two or more second isolation insulating layers 60.

Semiconductor devices of the inventive concepts may comprise any suitable type(s) of gate. In some embodiments, the first and second gates 90 a, 90 b may be normal gates useful for the operation of transistors. In some embodiments, the third gate 90 c may be a normal gate, a dummy gate (i.e., a gate that is not used for operation of a transistor), or an interconnection for transmitting a signal.

Each of Gates 90 a, 90 b, 90 c of the inventive concepts may comprise a corresponding one of gate electrodes 88 a, 88 b, 88 c and a corresponding one of the gate dielectric layers 80 a, 80 b, 80 c, respectively. The gate dielectric layers 80 a, 80 b, 80 c may extend in the second direction Y. Each of the gate dielectric layers 80 a, 80 b, 80 c may be disposed between a corresponding one of the gate electrode 88 a, 88 b, and 88 c and a corresponding one of the adjacent fin subregions 20 a, 20 b and the second isolation layer 60, respectively (e.g., between the corresponding one of the gate electrodes 88 a, 88 b, 88 c and the top surface of the corresponding one of the fin subregions 20 a, 20 b and the second isolation layer 60 disposed thereunder, respectively) and/or between the corresponding one of the gate electrodes 88 a, 88 b, 88 c and the adjacent source/drain region(s) 40. For example, the first gate 90 a may comprise a first gate electrode 88 a and a first gate dielectric layer 80 a, wherein the first gate dielectric layer 80 a is disposed between the first gate electrode 88 a and the first fin subregion 20 a disposed thereunder and the first source/drain region 40 a disposed therearound. Similarly, the third gate 90 c may comprise a third gate electrode 88 c and a third gate dielectric layer 80 c, wherein the third gate dielectric layer 80 c is disposed between the third gate electrode 88 c and the second isolation insulating layer 60 disposed thereunder and the first and second source/drain regions 40 a, 40 b disposed on either side. Accordingly, each of gate dielectric layers 80 a, and 80 b, 80 c may cover the sidewalls and bottom surface of the corresponding one of the gate electrodes 88 a 88 b, 88 c, as well as the top surface of the corresponding one of the fin region 20 a, 20 b and/or second isolation insulating layer 60. In some embodiments, the gate dielectric layers 80 a, 80 b, 80 c intersects the first isolation insulating layer 24.

Each of gate dielectric layers 80 a, 80 b, 80 c of the inventive concepts may comprise any suitable material(s), including, but not limited to, high-k dielectric materials having a dielectric constant higher than that of silicon oxide. In some embodiments, the gate dielectric layer 80 comprises hafnium oxide, hafnium-silicon oxide, lanthanum oxide, lanthanum-aluminum oxide, zirconium oxide, zirconium-silicon oxide, tantalum oxide, titanium oxide, barium-strontium-titanium oxide, barium-titanium oxide, strontium-titanium oxide, yttrium oxide, aluminum oxide, lead-scandium-tantalum oxide, and/or lead-zinc niobate.

Each of gate electrodes 88 a, 88 b, 88 c of the inventive concepts may comprise any suitable material(s), including, but not limited to, metals and metal nitrides. In some embodiments, each of gate electrodes 88 a, 88 b, 88 c comprises a first gate conductive layer 82 and a second gate conductive layer 84. The first gate conductive layer 82 may be disposed between the second gate conductive layer 84 and the gate dielectric layer 80 to control a work function of the gate electrode 88. In some embodiments, the second gate conductive layer 84 fills a space defined by the first gate conductive layer 82.

Each first gate conductive layer 82 of the inventive concepts may comprise any suitable material(s), including, but not limited to, metal and/or metal nitride. For example, in some embodiments, each first gate conductive layer 82 comprises titanium nitride (TiN), tantalum nitride (TaN), titanium carbide (TiC), titanium-aluminum (TiAl), titanium-aluminum carbide (TiAlC), titanium-aluminum nitride (TiAlN), tantalum carbide (TaC), and/or tantalum-aluminum nitride (TaAlN).

Each second gate conductive layer 84 of the inventive concepts may comprise any suitable material(s), including, but not limited to, metal and/or metal nitride. For example, in some embodiments, each second conductive layer 84 comprises tungsten (W) and/or aluminum (Al).

Gate electrodes 88 a, 88 b, 88 c of the inventive concepts may be formed using any suitable process(es), including, but not limited to, replacement processes and gate last processes.

Gate electrodes 88 a, 88 b, 88 c of the inventive concepts may have any suitable dimensions. In some embodiments, a lower portion of the third gate electrode 88 c (e.g., the lower surface of the third gate electrode 88 c) is substantially equal in size with or smaller than an upper portion of the second isolation insulating layer 60 (e.g., the upper surface of the second isolation insulating layer 60). For example, as shown in FIGS. 2A and 3A, in some embodiments, the width of the lower portion of the third gate electrode 88 c is substantially equal to, or smaller than the width of the upper portion of the second isolation insulating layer 60. In some embodiments, the top surfaces of the gate electrodes 88 a, 88 b, 88 c are coplanar or substantially coplanar.

Gates 90 a, 90 b, 90 c of the inventive concepts may have any suitable dimensions. In some embodiments, a lower portion of the third gate 90 c (e.g., the lower surface of the third gate 90 c) is substantially equal in size with or smaller than an upper portion of the second isolation insulating layer 60 (e.g., the upper surface of the second isolation insulating layer 60). For example, as shown in FIGS. 2A and 3A, in some embodiments, the width of the lower portion of the third gate 90 c is substantially equal to the width of the upper portion of the second isolation insulating layer 60.

In some embodiments, the top surfaces of the gates 90 a, 90 b, 90 c are coplanar or substantially coplanar. In some embodiments, the top surfaces of the gate dielectric layers 80 a, 80 b, 80 c are coplanar with or substantially coplanar with gate electrodes 88 a, 88 b, 88 c. As shown in FIGS. 2A to 2D, in some embodiments, the heights of the first and second gates 90 a, 90 b are substantially equal to the height of the third gate 90 c. As shown in FIGS. 3A to 3D, in some embodiments, the height of the third gate 90 c is greater than the heights of the first and second gates 90 a, 90 b.

As shown in FIGS. 2A to 2D, in some embodiments, the heights of the first and second gate electrodes 88 a, 88 b are substantially equal to the height of the third gate electrode 88 c. As shown in FIGS. 3A to 3D, in some embodiments, the height of a portion of the third gate electrode 88 c is greater than the heights of the first and second gate electrodes 88 a, 88 b.

In those embodiments in which the third gate 90 c is to be used as a normal gate or signal interconnection, signal delays may be reduced/prevented when the height of the third gate electrode 88 c is substantially equal to that of the first and second gate electrodes 88 a, 88 b. Accordingly, characteristics of semiconductor devices according to the inventive concepts may be improved.

Each of source/drain regions 40 a, 40 b may be disposed in a corresponding one of the subfin regions 20 a, 20 b on either side of the corresponding one of the gates 90 a, 90 b. For example, the first source/drain region 40 a may be formed in the first fin subregion 20 a adjacent to the sidewalls of the first gate 90 a, and the second source/drain region 40 b may be formed in the second fin subregion 20 b adjacent to the sidewalls of the second gate 9013.

Source/drain regions 40 a, 40 b of the inventive concepts may be formed using any suitable process(es), including, but not limited to, epitaxial filling processes. In some embodiments, each of source/drain regions 40 a, 40 b comprises epitaxial layers (e.g., epitaxial layer comprising one or more semiconductor materials) formed in recessed portion 36 of a fin region 20. For example, the first source/drain region 40 a may comprise epitaxial layers formed in a recessed portion 36 of the first fin subregion 20 a and the second source/drain region 40 b may comprise epitaxial layers formed in a recessed portion 36 of the second fin subregion 20 b. In some embodiments, at least one of the source/drain regions 40 a, 40 b lacks an epitaxial layer. In some embodiments, each of the source/drain regions 40 a, 40 b lacks an epitaxial layer.

Source/drain regions 40 a, 40 b of the inventive concepts may have any suitable dimensions. In some embodiments, the first and second source/drain regions 40 a, 40 b protrude above the top surfaces of the first and second fin subregions 20 a, 20 b, such that the first and second source/drain regions 40 a, 40 b comprise elevated source/drain structures. A cross section of each of the first and second source/drain regions 40 a, 40 may have a polygonal, elliptical shape, or circular shape. The bottom surfaces of the first and second source/drain regions 40 a, 40 b may be disposed in the pillar region 22 of the fin region 20 (i.e., the bottom surface of each source/drain region 40 may be higher than the top surface of the first isolation insulating layer 24). However, the inventive concepts are not limited thereto. In some embodiments, the bottom surfaces of the first and second source/drain regions 40 a, 40 b may be disposed in the fin region 20 lower than the top surface of the first isolation insulating layer 24.

Source/drain regions 40 a, 40 b of the inventive concepts may comprise any suitable dopant(s). In some embodiments, each of source/drain regions 40 a, 40 b comprises one or more P-type and/or one or more N-type dopants.

The source/drain regions 40 a, 40 b may be isolated from the gate electrodes 90 a, 90 b by gate spacers 34, respectively. For example, the first gate 90 a and the first source/drain region 40 a may be isolated from each other by one or more gate spacers 34 disposed between the sidewalls of the first gate 90 a and the sidewalls of the first source/drain region 40 a (e.g., between the sidewalls of the first gate dielectric layer 80 a and the sidewalls of the first source/drain region 40 a). Likewise, the second gate 90 b and the second source/drain region 40 b may be isolated from each other by one or more gate spacers 34 disposed between the sidewalls of the second gate 90 b and the sidewalls of the second source/drain region 40 b (e.g., between the sidewalls of the second gate dielectric layer 80 b and the sidewalls of the second source/drain region 40 b). Similarly, the third gate 90 c may isolated from the first and second source/drain regions 40 a, 40 b by one or more gate spacers 34 disposed between the sidewalls of the third gate 90 c and the sidewalls of the first and second source/drain regions 40 a, 40 b. Accordingly, shorts and leakage currents between the third gate electrode 88 c and the first and second source/drain regions 40 a, 40 b may be impeded/prevented.

Gate spacers 34 may be disposed adjacent to sidewalls of each of the gates 90 a, 90 b, 90 c. The gate spacers 34 may extend in the second direction Y together with the first to third gates 90 a, 90 b, 90 c and may directly contact corresponding ones of gate dielectric layers 80 a, 80 b, 80 c. The top surfaces of the gate spacers 34 may be planarized to be coplanar with or substantially coplanar with the top surfaces of the gates 90 a, 90 b, 90 c. The sidewalls of the second isolation insulating layer 60, which may be parallel to the second direction Y, may be substantially aligned with the inner sidewalls of the gate spacers 34 or the top surface of the second isolation insulating layer 60 may overlap with and be in contact with portions of bottom surfaces of the gate spacers 34. Meanwhile, the width of the upper portion of the second isolation insulating layer 60 may be wider than the lower portion of the third gate electrode 88 c.

Gate spacers 34 of the inventive concepts may comprise any suitable material(s), including, but not limited to, silicon nitride and/or silicon oxynitride.

If the first transistor 110 and/or the second transistor 120 is a PMOS transistor, the first source/drain region 40 a and/or the second source/drain region 40 b may include a compressive stress material. The compressive stress material may be a material (e.g., SiGe) having a lattice constant greater than that of silicon. The compressive stress material may apply a compressive stress to the first fin subregion 20 a under the first gate electrode 88 a and/or the second fin region 20 b under the second gate electrode 88 b, thereby improving mobility of carriers of a channel region.

If the first transistor 110 and/or the second transistor 120 is a NMOS transistor, the first source/drain region 40 a and/or the second source/drain region 40 b may include the same material as the substrate 10 or a tensile stress material. For example, if the substrate 10 is formed of silicon, the first source/drain region 40 a and/or the second source/drain region 40 b may include silicon or a material (e.g., SiC) having a lattice constant smaller than that of silicon.

Gaps between adjacent gate spacers 34 may be filled with one or more silicide layer, interlayer insulating layers 44 and/or protection patterns 46. For example, a silicide layer 42 may be formed on each of the source/drain regions 40 a, 40 b, an interlayer insulating layer 44 may be formed on each silicide layer 42, and each protective pattern 46 may be formed on each interlayer insulating layer 44. The top surfaces of the gap fillers (e.g., the top surfaces of protection patterns 46 formed on top surfaces of the silicide layers 42 and/or the interlayer insulating layers 44) may be coplanar with or substantially coplanar with the top surfaces of the gate spacers 34, and the gates 90 a, 90 b, 90 c.

Each silicide layer 42 of the inventive concepts may comprise any suitable material(s), including, but not limited to, nickel (Ni), cobalt (Co), platinum (Pt), and/or titanium (Ti).

Each interlayer insulating layer 44 of the inventive concepts may comprise any suitable material(s), including, but not limited to, silicon oxide and/or low-k dielectric materials having a dielectric constant lower than that of silicon oxide. In some embodiments, each interlayer insulating layer 44 comprises a porous insulating material. An air gap may be formed in each interlayer insulating layer 44.

Each protection pattern 46 of the inventive concepts may comprise any suitable material(s), including, but not limited to, nitride and/or oxynitride.

As noted above, FIGS. 3A to 3D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate semiconductor devices according to a second embodiment of the inventive concepts. Hereinafter, the descriptions of elements already described above with respect to FIGS. 1 and 2A to 2D will be omitted or mentioned only briefly so that differences between the first and second embodiments of the inventive concepts may be highlighted.

As shown in FIG. 3A, the height of the second isolation insulating layer 60 may be greater than the height(s) of the pillar region 22 in the first and second fin subregions 20 a, 20 b. For example, the top surfaces of the first fin subregion 20 a, the second fin subregion 20 b, and the second isolation insulating layer 60 may be coplanar or substantially coplanar, whereas the bottom surface of the second isolation insulating layer 60 may be lower than the bottom surface of the pillar region 22 in the first and second fin subregions 20 a, 20 b by a vertical distance p1 or more. In such embodiments, the height of the second isolation insulating layer 60 may be greater than that of the pillar region 22 in the first and second fin subregions 20 a, 20 b by at least height p1.

As shown in FIG. 3D, a top surface of a portion of the first isolation insulating layer 24 that is in contact with the second isolation insulating layer 60 in the second direction Y may be lower than the top surfaces of the first isolation insulating layer 24 that are in contact with the first and second fin subregions 20 a, 20 b. For example, the portion of the first isolation insulating layer 24 that is contact with the second isolation insulating layer 60 in the second direction Y may be recessed by a depth t1 to have a height h2 lower than the height h1 of the portions of the first isolation insulating layer 24 that are in contact with the bottom surfaces of the first and second fin subregions 20 a, 20 b. In some embodiments, the third gate 90 c extends into the recessed portion of the first isolation insulating layer 24. In such embodiments, the height of the third gate 90 c may be greater than that of the first gate 90 a and/or second gate 90 b by at least depth t1.

When the bottom surface of the second isolation insulating layer 60 is lower than the bottom surfaces of the first and second source/drain regions 40 a, 40 b of the first and second fin subregions 20 a, 20 b, an improved isolation characteristic may be realized between the first and second source/drain regions 40 a, 40 b. Thus, the isolation characteristic between the first and second transistors 110 and 120 may be improved by the second isolation insulating layer 60 as well as the punch-through stop layer 54, so the leakage current therebetween may be impeded/prevented.

FIG. 4A is a plan view illustrating semiconductor devices according to a third embodiment of the inventive concepts. FIGS. 4B to 4E are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 4A, respectively, to illustrate semiconductor devices according to the third embodiment of the inventive concepts. Hereinafter, the descriptions of elements already described above with respect to FIGS. 1 to 3D will be omitted or mentioned only briefly so that differences between the first and second embodiments of the inventive concepts may be highlighted.

As shown in FIG. 4B, the second isolation insulating layer 60 may have a U-shaped cross section. For example, the second isolation insulating layer 60 may comprise a vertical portion 60 a adjacent to the sidewalls of the first and second fin subregions 20 a, 20 b and a base portion 60 b adjacent to the bottom surface of the third gate 90 c. The second isolation insulating layer 60 may include a liner-shaped oxide layer that is self-alignedly formed on the top surface of the third fin subregion 20 c and the sidewalls of the first and second fin subregions 20 a, 20 b. For example, the sidewalls of the first and second fin subregions 20 a, 20 b and the top surface of the third fin subregion 20 c may be selectively and self-alignedly oxidized to form the second isolation insulating layer 60. In some embodiments, the second isolation insulating layer 60 is only formed on portions of the sidewalls of the first and second fin subregions 20 a, 20 b and of the top surface of the third fin subregion 20 c that have been exposed by the second recess region 53.

Also as shown in FIG. 4B, the height of the second isolation insulating layer 60 may be greater than the height(s) of the pillar region 22 in the first and second fin subregions 20 a, 20 b. For example, the top surfaces of the first fin subregion 20 a, the second fin subregion 20 b, and the second isolation insulating layer 60 may be coplanar or substantially coplanar, whereas the bottom surface of the second isolation insulating layer 60 may be lower than the bottom surface of the pillar region 22 in the first and second fin subregions 20 a, 20 b by a vertical distance p2 or more. In such embodiments, the height of the second isolation insulating layer 60 may be greater than that of the pillar region 22 in the first and second fin subregions 20 a, 20 b by at least height p2.

Also as shown in FIG. 4B, the third gate 90 c may at least partially fill that portion of the second recess region 53 that is not filled by the second isolation insulating layer 60. For example, the third gate 90 c may extend into the second recess region 53 and contact one or more interior surfaces of the second isolation insulating layer 60 (e.g., the interior sidewall(s) of the vertical portion 60 a of the second isolation insulating layer 60 and/or the top surface of the base portion 60 b of the second isolation insulating layer 60) and may extend in the second direction Y. In such embodiments, the third gate 90 c may include a portion disposed between the inner sidewalls of the second isolation insulating layer 60 and another portion disposed between the inner sidewalls of gate spacers 34 disposed on top of the third fin subregion 20 c. Accordingly, a bottom surface of the third gate 90 c disposed on the second isolation insulating layer 60 may be lower than the uppermost surface of the first isolation insulating layer 24, and the height of the third gate 90 c disposed on the second isolation insulating layer 60 may be greater than the heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. As shown in FIG. 4E, the heights of those portions of the first to third gates 90 a, 90 b, 90 c that are disposed on the first isolation insulating layer 24 may nevertheless be equal or substantially equal.

FIG. 5 is a plan view illustrating semiconductor devices according to embodiments of the inventive concepts. FIGS. 6A, 6B, 6C, and 6D are cross-sectional views taken along lines A-N, B-B′, C-C′, and D-D′ of FIG. 5, respectively, to illustrate semiconductor devices according to a fourth embodiment of the inventive concepts. FIGS. 7A, 7B, 7C, and 7D are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 5, respectively, to illustrate semiconductor devices according to a fifth embodiment of the inventive concepts. Hereinafter, the descriptions of elements already described above with respect to FIGS. 1 to 4E will be omitted or mentioned only briefly so that differences between the first and second embodiments of the inventive concepts may be highlighted.

As shown in FIGS. 5, 6A, 6B, 7A and 7B, the second isolation insulating layer 60 may comprise an oxide layer 64 and a filling insulation layer 66. The oxide layer 64 may extend into the second recessed region 53 and may have a U-shaped cross section. The filling insulation layer 66 may be disposed on the oxide layer 64 and may at least partially fill that portion of the second recess region 53 that is not filled by the oxide layer 64. The top surface(s) of the oxide layer 64 and/or filling insulation layer 66 may be coplanar with or substantially coplanar with the top surfaces of the first and second fin subregions 20 a, 20 b. Alternatively, the top surface(s) of the oxide layer 64 and/or filling insulation layer 66 may be higher than the top surfaces of the first and second fin subregions 20 a, 20 b. Accordingly, the height of the third gate 90 c may be less than the heights of the first and second gates 90 a, 90 b. Alternatively, as shown in FIG. 7A, the top surface of the filling insulation layer 66 may be lower than the top surfaces of the first and second fin subregions 20 a, 20 b. Accordingly, the height of the third gate 90 c may be greater than the heights of the first and second gates 90 a, 90 b.

Also as shown in FIGS. 6A and 7A, the height of the second isolation insulating layer 60 may be greater than the height(s) of the pillar region 22 in the first and second fin subregions 20 a, 20 b. For example, the top surfaces of the first fin subregion 20 a, the second fin subregion 20 b, and the second isolation insulating layer 60 may be coplanar or substantially coplanar, whereas the bottom surface of the second isolation insulating layer 60 may be lower than the bottom surface of the pillar region 22 in the first and second fin subregions 20 a, 20 b by a vertical distance p2 or more. In such embodiments, the height of the second isolation insulating layer 60 may be greater than that of the pillar region 22 in the first and second fin subregions 20 a, 20 b by at least height p2.

As shown in FIGS. 6D and 7D, the filling insulation layer 66 may extend further in the second direction Y than does the oxide layer 64. Thus, portions of the filling insulation layer 66 may be disposed directly on the first isolation insulating layer 24. The third gate 90 c may extend in the second direction Y on the filling insulation layer 66. In some embodiments, the filling insulation layer 66 may comprise discrete isolation insulating islands as described above. In this case, the third gate 90 c may cover a top surface and sidewalls of the filling insulation layer 66 and may extend in the second direction Y to intersect or cross the first isolation insulating layer 24.

FIGS. 8AA to 14CD are cross-sectional views illustrating processes according to some embodiments of the inventive concepts.

FIGS. 8AA to 8MA, 8AB to 8MB, 8AC to 8MC, and 8AD to 8MD are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate processes according to some embodiments of methods of manufacturing semiconductor devices according to the first embodiment of the inventive concepts.

FIGS. 9AA, 9AB, 9AC, and 9AD are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate processes according to some embodiments of methods of manufacturing semiconductor devices according to the first embodiment of the inventive concepts.

FIGS. 10AA to 10BA, 10AB to 10BB, 10AC to 10BC, and 10AD to 10BD are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate processes according to some embodiments of methods of manufacturing semiconductor devices according to the first embodiment of the inventive concepts.

FIGS. 11AA to 1113A, 11AB to 11BB, 11AC to 11BC, and 11AD to 11BD are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1, respectively, to illustrate processes according to some embodiments of methods of manufacturing semiconductor devices according to the second embodiment of the inventive concepts.

FIGS. 12AA to 12DA, 12AB to 12DB, 12AC to 12DC, and 12AD to 12DD are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 4A, respectively, to illustrate processes according to some embodiments of methods of manufacturing semiconductor devices according to the third embodiment of the inventive concepts.

FIGS. 13AA to 13DA, 13AB to 13DB, 13AC to 13DC, and 13AD to 13DD are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 5, respectively, to illustrate processes according to some embodiments of methods of manufacturing semiconductor devices according to the fourth embodiment of the inventive concepts.

FIGS. 14AA to 14CA, 14AB to 14CB, 14AC to 14CC, and 14AD to 14CD are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 5, respectively, to illustrate processes according to some embodiments of methods of manufacturing semiconductor devices according to the fifth embodiment of the inventive concepts.

As shown in FIGS. 8AA to 8AD, a plurality of fin regions 20 may be formed on the substrate 10.

Fin regions 20 may be formed on any suitable substrate 10. In some embodiments, the substrate 10 is a semiconductor substrate comprising one or more semiconductor materials, such as silicon (Si), germanium (Ge), silicon-germanium (SiGe), gallium-phosphorus (GaP), gallium-arsenic (GaAs), silicon-carbon (SiC), silicon-germanium-carbon (SiGeC), indium-arsenic (InAs), and/or indium-phosphorus (InP).

Fin regions 20 may be formed using any suitable process(es), including, but not limited to, etching and/or epitaxial growth processes. Accordingly, each fin region 20 may comprise a portion of the substrate 10 and/or an epitaxial layer on the substrate 10. In some embodiments, one or more of the fin regions 20 is an active region vertically protruding from the substrate 10.

Each fin region 20 may extend in a first direction X (e.g., an X-axis direction). The fin regions 20 may be separated from each other in a second direction Y (e.g., a Y-axis direction) different from the first direction X.

Although FIGS. 8AA to 8AD show two fin regions 20 isolated from each other in the second direction Y, it is to be understood that the inventive concepts are not limited to such embodiments. In some embodiments, three or more fin regions 20 may be present and isolated from each other.

The first direction X and the second direction Y may intersect each other at any suitable angle. In some embodiments, the first direction X and the second direction Y are perpendicular to each other. It is to be understood, however, that the inventive concepts are not limited to such embodiments.

The first direction X may be parallel to a length direction of one or more of the fin regions 20 (e.g., the length direction of each fin region 20), and the second direction Y may be parallel to a width direction of one or more of the fin regions 20 (e.g., the width direction of each fin region 20).

A first isolation insulating layer 24 may be formed between the fin regions 20 and may extend in the first direction X.

The first isolation insulating layer 24, which has a height h1, may be disposed directly on the substrate 10 and may be in direct contact with the sidewall(s) of one or more of the fin regions 20. In some embodiments, one or more of the fin regions 20 comprises a pillar region 22 that protrudes to a height greater than the height h1 of the first isolation insulating layer 24.

The first isolation insulating layer 24 may comprise any suitable material(s), including, but not limited to, oxide, nitride, oxynitride, and/or a low-k dielectric material.

As shown in FIGS. 8BA to 8BD, a plurality of sacrificial gates 30 a, 30 b, 30 c may be formed on the fin regions 20. For example, a first sacrificial gate 30 a and a second sacrificial gate 30 b may be disposed parallel to each other with a third sacrificial gate 30 c therebetween. Each of the sacrificial gates 30 a, 30 b, 30 c may extend in the second direction Y and may cover the top surface and/or sidewalls of each fin region 20. In some embodiments, one or more of the sacrificial gates 30 a, 30 b, 30 c may extend in the second direction Y and may cross the first isolation insulating layer 24.

The sacrificial gates 30 a, 30 b, 30 c may have any suitable dimensions. In some embodiments, the width of the third sacrificial gate 30 c may be equal to, substantially equal to or smaller than the width(s) of the first and/or second sacrificial gates 30 a, 30 b.

Each of the sacrificial gates 30 a, 30 b, 30 c may comprise any suitable material(s), including, but not limited to, poly-silicon and/or amorphous silicon.

A sacrificial gate dielectric layer 28 may be formed between each of the sacrificial gates 30 a, 30 b, 30 c and the fin region(s) 20 on which it is disposed. The sacrificial gate dielectric layer 28 may comprise any suitable material(s), including, but not limited to, one or more thermal oxide layers.

A gate capping layer 32 may be formed on a top surface of each of the first to third sacrificial gates 30 a, 30 b, 30 c. The gate capping layer 32 may comprise any suitable material(s), including, but not limited to, silicon nitrides and/or silicon oxynitrides.

Gate spacers 34 may be formed on the sidewalls of each of the gates 30 a, 30 b, 30 c. The gate spacers 34 may extend vertically to cover the sidewalls of the sacrificial gate dielectric layer 28 and/or the gate capping layers 32. The gate spacers 34 may extend in parallel with the sacrificial gates 30 a, 30 b, 30 c in the second direction Y. The gate spacer 34 may comprise any suitable material(s), including, but not limited to, silicon nitride and/or silicon oxynitride.

As shown in FIGS. 8CA to 8CD, portions of the fin regions 20 adjacent to the gate spacers 34 may be removed to form first recess regions 36.

The first recess regions 36 may be formed using any suitable process(es), including, but not limited to, dry and/or wet etching processes. In some embodiments, the gate capping layers 32 and the gate spacers 34 are used as an etch mask to form first recess regions 36.

The first recess regions may have any suitable dimensions. Bottom surfaces of the first recess regions 36 may be disposed in the pillar region 22. However, the inventive concepts are not limited thereto. In other embodiments, the bottom surfaces of the first recess regions 36 may be disposed in the fin region 20 lower than a top surface of the first isolation insulating layer 24. Interior sidewalls of the first recess regions 36 may be aligned with exterior sidewalls of the gate spacers 34. In some embodiments, the first recess regions 36 may be enlarged to partially expose bottom surfaces of the gate spacers 34.

As shown in FIGS. 8DA to 8DD, an epitaxial layer 38 may be formed in each of the first recess regions 36. The epitaxial layer 38 may be formed by selectively epitaxial-growing a semiconductor material. If a PMOS transistor is to be formed, the epitaxial layer 38 may be formed by epitaxial-growing a compressive stress material. The compressive stress material may have a lattice constant greater than that of silicon. For example, silicon-germanium (SiGe) may be epitaxial-grown to form a SiGe epitaxial layer. Alternatively, if an NMOS transistor is to be formed, the epitaxial layer 38 may be formed by epitaxial-growing the same material as the substrate 10 or a tensile stress material. For example, if the substrate 10 comprises Si, Si or SiC may be epitaxially grown to form a Si epitaxial layer or a SiC epitaxial layer having a lattice constant smaller than that of Si. A top surface of the epitaxial layer 38 may be formed to be higher than the top surface of the fin region 20. A cross section of the epitaxial layer 38 may have a polygonal shape, a circular shape, or an elliptical shape.

As shown in FIGS. 8EA to 8ED, the epitaxial layers 38 may be doped with dopants to form first and second source/drain regions 40 a, 40 b. The first source/drain regions 40 a may be formed to be adjacent to sidewalls of the first sacrificial gate 30 a, and the second source/drain regions 40 b may be formed to be adjacent to sidewalls of the second sacrificial gate 30 b. In some embodiments, the epitaxial layers 38 may be doped with P-type or N-type dopants in-situ to form the first and second source/drain regions 40 a, 40 b when the epitaxial layers 38 are formed. In other embodiments, the first and second source/drain regions 40 a, 40 b may be formed by ion-implanting P-type or N-type dopants into the epitaxial layers 38. Since the first and second drain regions 40 a, 40 b are formed in the epitaxial layers 38, the first and second drain regions 40 a, 40 b may have an elevated source/drain structure. In FIG. 8EA, bottom surfaces of the first and second source/drain regions 40 a, 40 b are disposed in the pillar region 22 higher than the top surface (e.g., a dotted line) of the first isolation insulating layer 24. However, the inventive concepts are not limited thereto. In other embodiments, the bottom surfaces of the first and second source/drain regions 40 a, 40 b may be disposed in the fin region 20 lower than the top surface (e.g., the dotted line) of the first isolation insulating layer 24. In some embodiments, if the epitaxial layer 38 is not formed, dopants may be injected into the fin regions 20 to form the first and/or second source/drain regions 40 a and/or 40 b.

The first and second source/drain regions 40 a, 40 b may be isolated from the first to third sacrificial gates 30 a, 30 b, 30 c by the gate spacers 34. A silicide layer 42 may be formed on each of the first and second source/drain regions 40 a, 40 b. The silicide layer 42 may include at least one metal of nickel (Ni), cobalt (Co), platinum (Pt), or titanium (Ti). An interlayer insulating layer 44 may be formed on the silicide layers 42. The interlayer insulating layer 44 may include an oxide or a low-k dielectric material. The interlayer insulating layer 44 may include a porous material. The interlayer insulating layer 44 may include an air gap therein. The interlayer insulating layer 44 may be formed using a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, or a spin coating process. The interlayer insulating layer 44 may be formed to cover the gate capping layers 32 and may be then etched by an etch-back process until the gate capping layer 32 and portions of the gate spacers 34 are exposed. The interlayer insulating layer 44 may partially fill a space between the gate spacers 34 opposite to each other. A protection layer 46 a may be formed on the interlayer insulating layer 44. The protection layer 46 a may be formed to cover the gate capping layer 32 and the gate spacer 34 which are exposed by the interlayer insulating layer 44. For example, the protection layer 46 a may include a nitride and/or an oxynitride.

As shown in FIGS. 8FA to 8FD, protection patterns 46 spaced apart from each other may be formed on the interlayer insulating layer 44. For example, the protection layer 46 a and the gate capping layer 32 may be planarized by, for example, a chemical mechanical polishing (CMP) process, so the gate capping layer 32 and a portion of the protection layer 46 a thereon may be removed. At this time, the gate spacer 34 may be partially removed. As a result, top surfaces of the first to third sacrificial gates 30 a, 30 b, 30 c may be exposed and the protection patterns 46 may be formed on only the interlayer insulating layer 44.

As shown in FIGS. 8GA to 8GD, a first mask 50 may be formed to cover the first and second sacrificial gates 30 a, 30 b and to have a first opening 51 exposing the third sacrificial gate 30 c. The first opening 51 may have a width greater than the width of the third sacrificial gate 30 c in the first direction X and may extend in the second direction Y. The first opening 51 may partially expose the gate spacers 34 and the protection patterns 46 which are adjacent to the third sacrificial gate 30 c. The first mask 50 may include a hard mask layer or a photoresist layer. The hard mask layer may be formed of, for example, a spin-on-hardmask (SOH) layer. The third sacrificial gate 30 c and the sacrificial gate dielectric layer 28 may be removed using the first mask 50 as an etch mask to form a first groove 52. The first groove 52 may extend in the second direction Y. The first and second source/drain regions 40 a, 40 b adjacent to the third sacrificial gate 30 c are covered with the gate spacers 34 and the protection patterns 46 during the formation of the first groove 52 not to be exposed, and thus, it is possible to protect/prevent the first and second source/drain regions 40 a, 40 b from being etched. The first groove 52 may expose portions of the fin regions 20 (e.g., portions of the pillar regions 22). In addition, the first groove 52 may partially expose the first isolation insulating layer 24.

As shown in FIGS. 8HA to 8HD, the fin region 20 exposed by the first groove 52 may be trimmed to form a trimmed pillar region 22 a. For example, a portion of the pillar region 22 may be removed through the trimming process by, for example, a thickness S. Each of the top surface and the sidewalls of the pillar region 22 may be removed by the thickness S. For example, the thickness S may be in a range of 1/20 to ⅓ of the width of each of the fin regions 20.

As shown in FIGS. 8IA to 8ID, the first mask 50 may be removed, and the trimmed pillar region 22 a may be then oxidized to form a second isolation insulating layer 60. The second isolation insulating layer 60 may be formed to be self-aligned with the first groove 52 by the oxidation of the trimmed pillar region 22 a. For example, the second isolation insulating layer 60 may be an oxide layer that is formed by oxidizing the trimmed pillar region 22 a using a plasma oxidation process. For example, the trimmed pillar region 22 a may be oxidized using an oxygen gas or an ozone gas at a temperature of 20° C. to 800° C. under a plasma atmosphere to form the second isolation insulating layer 60. In other embodiments, the second isolation insulating layer 60 may be an oxide layer that is formed by oxidizing the trimmed pillar region 22 a using a thermal oxidation process. For example, the second isolation insulating layer 60 may be an oxide layer which is formed by oxidizing the trimmed pillar region 22 a using a dry oxidation process, a wet oxidation process, or a thermal radical oxidation process.

A first fin subregion 20 a and a second fin subregion 20 b may be formed in each of the fin regions 20. The first fin subregion 20 a and the second fin subregion 20 b may be separated from each other in the first direction X by the second isolation insulating layer 60. In addition, a third fin subregion 20 c connected to the substrate 10 may be formed in each fin region 20 under the second isolation insulating layer 60.

The second isolation insulating layer 60 may be a discrete isolation insulating island (e.g., an island-shaped pattern) having a top surface and sidewalls. For example, sidewalls of the second isolation insulating layer 60 which are arranged in the second direction Y may be exposed by the first groove 52. In other words, the sidewalls of the second isolation insulating layer 60 exposed by the first groove 52 may be parallel to the first direction X. Sidewalls of the second isolation insulating layer 60 which are arranged in the first direction X may be in contact with a sidewall of the first fin subregion 20 a and a sidewall of the second fin subregion 20 b which face each other. In other words, the sidewalls of the second isolation insulating layer 60 which are in contact with the sidewalls of the first and second fin subregions 20 a, 20 b may be parallel to the second direction Y. A plurality of the second isolation insulating layers 60 may be spaced apart from and aligned with each other in the second direction Y. In some embodiments, the sidewalls of the second isolation insulating layer 60 arranged in the first direction X may be in contact with the first and second source/drain regions 40 a, 40 b. The second isolation insulating layer 60 may have sidewalls aligned with inner sidewalls of the gate spacers 34. Alternatively, a width in the first direction X of the second isolation insulating layer 60 may be widened, so a top surface of the second isolation insulating layer 60 may partially overlap with a bottom surface of the gate spacer 34. A bottom surface of the isolation insulating layer 60 may be formed to be lower than the top surface of the first isolation insulating layer 24. For example, a portion of the fin region 20 lower than the top surface of the first isolation insulating layer 24 may be oxidized when the trimmed pillar region 22 a is oxidized. In some embodiments, the trimming process of the pillar region 22 may be omitted and the pillar region 22 may be oxidized to form the second isolation insulating layer 60.

As shown in FIGS. 8JA to 8JD, a punch-through stop layer 54 may be formed in the third fin subregion 20 c under the second isolation insulating layer 60. The punch-through stop layer 54 may extend into the first and second fin subregions 20 a, 20 b. A conductivity type of the punch-through stop layer 54 may be different from that of the first and second source/drain regions 40 a, 40 b. For example, the punch-through stop layer 54 may include dopants of which a conductivity type is different from that of the first and second source/drain regions 40 a, 40 b. For example, if the first and second source/drain regions 40 a, 40 b include N-type dopants, the punch-through stop layer 54 may include P-type dopants. Alternatively, if the first and second source/drain regions 40 a, 40 b include P-type dopants, the punch-through stop layer 54 may include N-type dopants. For example, the punch-through stop layer 54 may include the P-type dopants such as boron (B) or indium (In). Alternatively, the punch-through stop layer 54 may include the N-type dopants such as phosphorus (P), arsenic (As), or strontium (Sr). The punch-through stop layer 54 may have a dopant concentration in a range of about 10¹⁵ atoms/cm³ to about 10²⁰ atoms/cm³. For example, dopants such as boron (B), BF₂, indium (In), arsenic (As), phosphorus (P), or strontium (Sr) may be ion-implanted in the third fin subregion 20 c under the second isolation insulating layer 60 with a dose of about 10¹¹ atoms/cm² to about 10¹⁵ atoms/cm² to form the punch-through stop layer 54. For example, an angle of the ion implantation may be in a range of about 10 degrees to about 50 degrees with respect to the substrate 10.

As shown in FIGS. 8KA to 8KD, a second groove 62 may be formed on each of the first and second fin subregions 20 a, 20 b. For example, the second grooves 62 may formed by sequentially removing the first and second sacrificial gates 30 a, 30 b and the sacrificial gate dielectric layer 28. For example, the first and second sacrificial gates 30 a, 30 b may be selectively removed using the gate spacers 34 and the protection patterns 46 as an etch mask. When the sacrificial gate dielectric layer 28 is removed, a portion of the second isolation insulating layer 60 may be removed. Top surfaces and sidewalls of the first and second fin subregions 20 a, 20 b may be partially exposed by the second grooves 62. For example, portions of the pillar regions 22 of the first and second fin subregions 20 a, 20 b may be exposed by the second grooves 62. In addition, portions of the first isolation insulating layer 24 may be exposed by the second grooves 62.

As shown in FIGS. 8LA to 8LD, a gate dielectric layer 80, a first gate conductive layer 82, and a second gate conductive layer 84 may be sequentially formed to fill the first and second grooves 52 and 62. For example, the gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be formed by a replacement process refilling grooves formed by the removal of the sacrificial gates 30 a, 30 b, 30 c. The gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may cover top surfaces and sidewalls of the pillar regions 22 of the fin regions 20. In addition, the gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may cover the top surface and the sidewalls of the second isolation insulating layer 60. The gate dielectric layer 80 may include a high-k dielectric material having a dielectric constant higher than that of silicon oxide. For example, the gate dielectric layer 80 may include at least one of, but not limited to, hafnium oxide, hafnium-silicon oxide, lanthanum oxide, lanthanum-aluminum oxide, zirconium oxide, zirconium-silicon oxide, tantalum oxide, titanium oxide, barium-strontium-titanium oxide, barium-titanium oxide, strontium-titanium oxide, yttrium oxide, aluminum oxide, lead-scandium-tantalum oxide, or lead-zinc niobate.

The gate dielectric layer 80 may be formed using an ALD process or a CVD process. The first gate conductive layer 82 may include a material capable of controlling a work function of a gate electrode. The second gate conductive layer 84 may fill spaces defined by the first gate conductive layer 82. For example, the first gate conductive layer 82 may include at least one of titanium nitride (TiN), tantalum nitride (TaN), titanium carbide (TiC), titanium-aluminum (TiAl), titanium-aluminum carbide (TiAlC), titanium-aluminum nitride (TiAlN), tantalum carbide (TaC), or tantalum-aluminum nitride (TaAlN). The second gate conductive layer 84 may include a metal. For example, the second conductive layer 84 may include tungsten (W) or aluminum (Al). Each of the first and second gate conductive layers 82, 84 may be formed using an ALD process or a CVD process.

As shown in FIGS. 8MA to 8MD, a first gate 90 a, a second gate 90 b, and a third gate 90 c may be formed on the first fin subregion 20 a, the second fin subregion 20 b, and the second isolation insulating layer 60, respectively. The first gate 90 a may include a first gate dielectric layer 80 a and a first gate electrode 88 a, the second gate 90 b may include a second gate dielectric layer 80 b and a second gate electrode 88 b, and the third gate 90 c may include a third gate dielectric layer 80 c and a third gate electrode 88 c. To form the first to third gates 90 a, 90 b, 90 c, the second gate conductive layer 84, the first gate conductive layer 82, and the gate dielectric layers 80 a, 80 b, 80 c may be planarized by, for example, a CMP method until the protection patterns 46 and the gate spacers 34 are exposed. Thus, the gate dielectric layer 80 and the first and second gate conductive layers 82, 84 may be removed from top surfaces of the protection patterns 46 and the gate spacers 34 but may remain in the first and second grooves 52, 62. As a result, the first gate electrode 88 a may be formed to include the first and second gate conductive layers 82 and 84 intersecting the first fin subregion 20 a, and the second gate electrode 88 b may be formed to include the first and second gate conductive layers 82, 84 intersecting the second fin subregion 20 b. In addition, the third gate electrode 88 c may be formed to include the first and second conductive layers 82, 84 intersecting the second isolation insulating layer 60. The first gate dielectric layer 80 a may be disposed between the first fin subregion 20 a and the first gate electrode 88 a, the second gate dielectric layer 80 b may be disposed between the second fin subregion 20 b and the second gate electrode 88 b, and the third gate dielectric layer 80 c may be disposed between the second isolation insulating layer 60 and the third gate electrode 88 c. Each of the first through third gate dielectric layers 80 a, 80 b, 80 c may surround sidewalls and a bottom surface of the corresponding one of the first to third gate electrodes 88 a, 88 b, 88 c and may extend in the second direction Y. Each of the first and second gate electrodes 88 a, 88 b and each of the gate dielectric layers 80 a, 80 b corresponding thereto may cover the top surface and the sidewalls of each of the first and second fin subregions 20 a, 20 b and may extend in the second direction Y. The third gate electrode 88 c and the third gate dielectric layer 80 c may surround the top surface and the sidewalls of the second isolation insulating layer 60 and may extend in the second direction Y. Accordingly, the first and second gates 90 a, 90 b respectively intersecting the first and second fin subregions 20 a, 20 b may extend in the second direction Y. The first gate 90 a may cover the top surface and the sidewalls of the first fin subregion 20 a and may extend in the second direction Y to intersect the first isolation insulating layer 24. The second gate 90 b may cover the top surface and the sidewalls of the second fin subregion 20 b and may extend in the second direction Y to intersect the first isolation insulating layer 24. The third gate 90 c may cover the top surface and the sidewalls of the second isolation insulating layer 60 and may extend in the second direction Y to intersect the first isolation insulating layer 24. For example, the third gate 90 c may cover the sidewalls and the top surface of the second isolation insulating layer 60 which are exposed between the gate spacers 34 adjacent to the sidewalls of the third gate 90 c and may extend in the second direction Y to intersect the first isolation insulating layer 24. The first and second gates 90 a, 90 b may be used as normal gates for operation of transistors, but the third gate 90 c may be used as a dummy gate that is not used for operation of a transistor. Alternatively, the third gate 90 c may be used as a signal-transmitting interconnection or a normal gate.

A width of the third gate 90 c may be substantially equal to or smaller than widths of the first and second gates 90 a, 90 b. Heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b may be substantially equal to a height of the third gate 90 c disposed on the second isolation insulating layer 60. For example, heights of the first and second gate electrodes 88 a and 88 b disposed on the first and second fin subregions 20 a, 20 b may be substantially equal to a height of the third gate electrode 88 c disposed on the second isolation insulating layer 60. Accordingly, in the event that the third gate electrode 88 c is used as a signal-transmitting interconnection or a normal gate electrode, the third gate electrode 88 c has the same thickness as other gate electrodes 88 a and 88 b to reduce/prevent a signal delay phenomenon through the third gate electrode 88 c. As a result, characteristics of the semiconductor device according to the inventive concepts may be improved.

A first transistor 110 including the first gate 90 a and the first source/drain regions 40 a may be formed on the first fin subregion 20 a, and a second transistor 120 including the second gate 90 b and the second source/drain regions 40 b may be formed on the second fin subregion 20 b. The first transistor 110 and/or the second transistor 120 may be an N-type transistor and/or a P-type transistor. The second isolation insulating layer 60 may isolate the first transistor 110 from the second transistor 120. In addition, the punch-through stop layer 54 may further improve the isolation characteristic between the transistors 110 and 120. Thus, the first transistor 110 may be electrically and physically isolated from the second transistor 120 by the second isolation insulating layer 60 and the punch-through stop layer 54.

As described above, since the fin region 20 exposed by the selective removal of the third sacrificial gate 30 c is oxidized to form the second isolation insulating layer 60 during the replacement process, the formation process of the second isolation insulating layer 60 may be simplified. For example, it is possible to omit additional photolithography process and etching process for formation of a trench which may be required for the formation of the second isolation insulating layer 60, and thus, productivity of the semiconductor device may be improved. In addition, the third gate 90 c may be formed to be self-aligned with the top surface of the second isolation insulating layer 60 in the first groove 52 to reduce/prevent misalignment between the third gate 90 c and the second isolation insulating layer 60. Thus, the degree of freedom with respect to the width of the third gate 90 c may be secured, and the short and/or the leakage current between the third gate electrode 88 c and the first or second source/drain region 40 a or 40 b may be impeded/prevented.

FIGS. 9A to 9D are cross-sectional views respectively taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1 to illustrate a process of another embodiment of a method of manufacturing the semiconductor device according to the first embodiment of the inventive concepts. Hereinafter, the descriptions to the same elements as described in FIGS. 8AA to 8MD will be omitted or mentioned briefly. In other words, differences between the present embodiment and the embodiment of FIGS. 8AA to 8MD will be mainly described.

As shown in FIGS. 9A to 9D, according to the present embodiment, the second isolation insulating layer illustrated in FIGS. 8IA to 8ID may be formed using a separation by implanted oxygen (SIMOX) method. For example, oxygen (O₂) may be ion-implanted through an entire surface of the fin region 20 exposed by the first groove 52. The implanted oxygen 55 may be thermally treated to react with silicon of the fin region 20, so an oxide layer may be formed. In some embodiments, the thermal treatment of the fin region 20 including the implanted oxygen 55 may include a thermal oxidation process or the plasma oxidation process described with reference to FIGS. FIGS. 8IA to 8ID.

FIGS. 10AA to 10BD are cross-sectional views illustrating a process of still another embodiment of a method of manufacturing the semiconductor device according to the first embodiment of the inventive concepts. FIGS. 10AA and 10BA are cross-sectional views taken along a line A-A of FIG. 1, and FIGS. 10AB and 10BB are cross-sectional views taken along a line B-B′ of FIG. 1. FIGS. 10AC and 10BC are cross-sectional views taken along a line C-C′ of FIG. 1, and FIGS. 10AD and 10BD are cross-sectional views taken along a line D-D′ of FIG. 1. Hereinafter, the descriptions of elements already described above with respect to FIGS. 8AA to 8MD will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiment of FIGS. 8AA to 8MD may be highlighted.

As shown in FIGS. 10AA to 10AD, a punch-through stop layer 54 may be formed under the trimmed pillar regions 22 a before the formation of the second isolation insulating layer 60. Dopants may be ion-implanted under the same condition as described with reference to FIGS. 8JA to 8JD to form the punch-through stop layer 54.

As shown in FIGS. 10BA to 10BD, thereafter, the first mask 50 may be removed and then the trimmed pillar regions 22 a under which the punch-through stop layer 54 is formed may be oxidized to form the second isolation insulating layer 60. The second isolation insulating layer 60 may be an oxide layer formed under the same condition as described with reference to FIGS. 8IA to 8ID.

FIGS. 11AA to 11DB are cross-sectional views illustrating some processes of a method of manufacturing the semiconductor device according to the second embodiment of the inventive concepts. FIGS. 11AA and 11BA are cross-sectional views taken along a line A-A′ of FIG. 1, and FIGS. 11AB and 11BB are cross-sectional views taken along a line B-B′ of FIG. 1. FIGS. 11AC and 11BC are cross-sectional views taken along a line C-C′ of FIG. 1, and FIGS. 11AD and 11BD are cross-sectional views taken along a line D-D′ of FIG. 1. Hereinafter, the descriptions of elements already described above with respect to FIGS. 8AA to 8MD will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiment of FIGS. 8AA to 8MD may be highlighted.

As shown in FIGS. 11AA to 11AD, the first isolation insulating layer 24 exposed by the first groove 52 may be removed by a thickness t1. For example, a top surface of the first isolation insulating layer 24 exposed by the first groove 52 may be lower than the top surface of the first isolation insulating layer 24 disposed under the first and second sacrificial gates 30 a, 30 b by the thickness t1. A height h2 of the first isolation insulating layer 24 exposed by the first groove 24 may be a value obtained by subtracting the thickness t1 from a height h1 of the first isolation insulating layer 24 disposed under the first and second sacrificial gates 30 a, 30 b. Thus, a height of a pillar region 22 b exposed by the first groove 52 may be greater than the height of the pillar region 22 of FIG. 8GB by the thickness t1.

As shown in FIGS. 11BA to 11BD, the pillar region 22 b exposed by the first groove 52 may be oxidized to form a second isolation insulating layer 60. A first fin subregion 20 a and a second fin subregion 20 b may be isolated or separated from each other by the second isolation insulating layer 60. The pillar region 22 b may be oxidized under the same or similar oxidation condition with the trimmed pillar region 22 a as described with reference to FIGS. FIGS. 8IA to 8ID to form the second isolation insulating layer 60. Accordingly, a bottom surface of the second isolation insulating layer 60 may be lower than the top surface of the first isolation insulating layer 24 by a vertical distance p1, so a height of the second isolation insulating layer 60 may be increased to improve the isolation characteristic between the first and second fin subregions 20 a, 20 b. A punch-through stop layer 54 may be formed in a third fin subregion 20 c under the second isolation insulating layer 60. The punch-through stop layer 54 may be a dopant region formed under the same condition as described with reference to FIGS. 8JA to 8JD. Subsequent processes may be the same as described with reference to FIGS. 8KA to 8MD.

FIGS. 12AA to 12DD are cross-sectional views illustrating some processes of a method of manufacturing the semiconductor device according to the third embodiment of the inventive concepts. FIGS. 12AA to 12DA are cross-sectional views taken along a line A-A′ of FIG. 4A, and FIGS. 12AB to 12DB are cross-sectional views taken along a line B-B′ of FIG. 4A. FIGS. 12AC to 12DC are cross-sectional views taken along a line C-C′ of FIG. 4A, and FIGS. 12AD to 12DD are cross-sectional views taken along a line D-D′ of FIG. 4A. Hereinafter, the descriptions of elements already described above with respect to FIGS. 8AA to 8MD will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiment of FIGS. 8AA to 8MD may be highlighted.

As shown in FIGS. 12AA to 12AD, a portion of the fin region 20 exposed by the first groove 52 may be removed using the first mask 50 as an etch mask to form a second recess region 53. For example, the pillar region 22 exposed by the first groove region 52 may be removed and the fin region 20 may be further etched by a depth t2 to form the second recess region 53. Thus, a bottom surface of the second recess region 53 may be lower than the top surface of the first isolation insulating layer 24. The fin region 20 may have structures separated from each other in the first direction X by the second recess region 53.

As shown in FIGS. 12BA to 12BD, after the first mask 50 is removed, the fin region 20 exposed by the second recess region 53 may be oxidized to form a second isolation insulating layer 60. The second isolation insulating layer 60 may be a liner-shaped oxide layer self-alignedly formed on the bottom surface and inner sidewalls of the second recess region 53. The second isolation insulating layer 60 may have a U-shaped cross section. The portion of the fin region 20 exposed by the second recess region 53 may be oxidized by a plasma oxidation process to form the second isolation insulating layer 60. For example, the fin region 20 exposed through the second recess region 53 may be oxidized using an oxygen gas or an ozone gas at a temperature of 20° C. to 800° C. under a plasma atmosphere to form the second isolation insulating layer 60. In other embodiments, the fin region 20 exposed through the second recess region 53 may be oxidized by a thermal oxidation process to form the second isolation insulating layer 60. For example, the thermal oxidation process may be a dry oxidation process, a wet oxidation process, or a thermal radical oxidation process. Alternatively, the second isolation insulating layer 60 may be formed by the SIMOX method described with reference to FIGS. 9AA to 9AD. The second isolation insulating layer 60 may include a vertical portion 60 a formed on the inner sidewall of the second recess region 53 and a base portion 60 b formed on the bottom surface of the second recess region 53. The vertical portion 60 a may partially overlap with the gate spacer 34, and thus, a width of a space defined by the second isolation insulating layer 60 in the second recess region 53 may be smaller than a width of the first groove 52 in the first direction X. A bottom surface of the second isolation insulating layer 60 may be lower than the top surface of the first isolation insulating layer 24 by a vertical distance p2. The second isolation insulating layer 60 may be in contact with the first and second source/drain regions 40 a, 40 b. The first fin subregion 20 a may be isolated from the second fin subregion 20 b by the second isolation insulating layer 60. A punch-through stop layer 54 may be formed in a third fin subregion 20 c under the second isolation insulating layer 60. The punch-through stop layer 54 may be a dopant region formed by ion-implanting dopants using, for example, the same method as described with reference to FIGS. FIGS. 8JA to 8JD. The punch-through stop layer 54 may be formed before or after the formation of the second isolation insulating layer 60.

As shown in FIGS. 12CA to 12CD, the first and second sacrificial gates 30 a, 30 b and the sacrificial gate dielectric layers 28 may be selectively removed to form second grooves 62. A gate dielectric layer 80, a first gate conductive layer 82, and a second gate conductive layer 84 may be sequentially formed on the substrate 10 to fill the first groove 52 and the second grooves 62. The gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be formed of the same materials as described with reference to FIGS. 8LA to 8LD by the same processes as described with reference to FIGS. 8LA to 8LD.

Referring to FIGS. 12DA to 12DD, the gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be planarized by, for example, a CMP process. Thus, a first gate 90 a including a first gate dielectric layer 80 a and a first gate electrode 88 a may be formed on the first fin subregion 20 a, a second gate 90 b including a second gate dielectric layer 80 b and a second gate electrode 88 b may be formed on the second fin subregion 20 b, and a third gate 90 c including a third gate dielectric layer 80 c and a third gate electrode 88 c may be formed on the second isolation insulating layer 60. Each of the first to third gate electrodes 88 a, 88 b, 88 c may include the first gate conductive layer 82 and the second gate conductive layer 84. The third gate 90 c may cover the vertical portions 60 a and the base portion 60 b and may extend in the second direction Y. A bottom surface of the third gate 90 c disposed on the base portion 60 b may be lower than the top surface of the first isolation insulating layer 24. A height of the third gate 90 c disposed on the base portion 60 b may be greater than heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. Heights of the first to third gates 90 a, 90 b, 90 c disposed on the first isolation insulating layer 24 may be substantially equal to each other.

FIGS. 13AA to 13DD are cross-sectional views illustrating some processes of a method of manufacturing the semiconductor device according to the fourth embodiment of the inventive concepts. FIGS. 13AA to 13DA are cross-sectional views taken along a line A-A′ of FIG. 5, and FIGS. 13AB to 13DB are cross-sectional views taken along a line B-B′ of FIG. 5. FIGS. 13AC to 13DC are cross-sectional views taken along a line C-C′ of FIG. 5, and FIGS. 13AD to 13DD are cross-sectional views taken along a line D-D′ of FIG. 5. Hereinafter, the descriptions of elements already described above with respect to FIGS. 8AA to 8MD will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiment of FIGS. 8AA to 8MD may be highlighted.

As shown in FIGS. 13AA to 13AD, the fin region 20 exposed by the inner sidewalls and the bottom surface of the second recess region 53 of FIGS. 12AA to 12AD may be oxidized to form an oxide layer 64. The oxide layer 64 may be formed by, for example, the same process as the formation process of the second isolation insulating layer 60 described with reference to FIGS. 12BA to 12BD. A bottom surface of the oxide layer 64 may be lower than the top surface of the first isolation insulating layer 24 by a vertical distance p2. A filling insulation layer 66 may be formed on the oxide layer 64. For example, the filling insulation layer 66 may be formed to fill the first groove 52 and the second recess region 53. For example, the filling insulation layer 66 may include an oxide, an oxynitride, and/or a nitride.

As shown in FIGS. 13BA to 13BD, the filling insulation layer 66 may be recessed to expose the first groove 52. For example, a blanket etch-back process may be performed to remove a portion of the filling insulation layer 66 formed on the protection patterns 46 and the sacrificial gates 30 a, 30 b and another portion of the filling insulation layer 66 formed in the first groove 52. For example, the portions of the filling insulation layer 66 may be selectively removed with respect to the protection patterns 46 and the sacrificial gates 30 a, 30 b. Thus, a second isolation insulating layer 60 may be formed to include the oxide layer 64 and the filling insulation layer 66 which fill the second recess region 53. In some embodiments, a top surface of the filling insulation layer 66 formed in the second recess region 53 may be a little higher than the top surfaces of the first and second fin subregions 20 a, 20 b. For example, the top surface of the filling insulation layer 66 may be substantially coplanar with a top surface of the sacrificial gate dielectric layer 28. Alternatively, the top surface of the filling insulation layer 66 may be formed to be higher than the top surface of the sacrificial gate dielectric layer 28.

The filling insulation layer 66 may be a pattern extending in the second direction Y. The filling insulation layer 66 may also be formed on the first isolation insulating layer 24. In some embodiments, the filling insulation layer 66 may be formed to be a discrete isolation insulating island (e.g., an island-shaped pattern). In this case, a plurality of filling insulation layers 66 formed under the first groove 52 may be spaced apart from each other in the second direction Y. Thus, the filling insulation layer 66 as well as the oxide layer 64 self-alignedly formed may have an isolated shape like the second isolation insulating layer 60 illustrated in FIG. 1.

As shown in FIGS. 13CA to 13CD, the first and second sacrificial gates 30 a, 30 b and the sacrificial gate dielectric layers 28 are selectively removed. A portion of the filling insulation layer 66 may be removed during the removal of the sacrificial gate dielectric layers 28, so a top surface of the filling insulation layer 66 may be substantially coplanar with the top surfaces of the first and second fin subregions 20 a, 20 b. Alternatively, the top surface of the filling insulation layer 66 may be higher than the top surfaces of the first and second fin subregions 20 a, 20 b. Thereafter, a gate dielectric layer 80, a first gate conductive layer 82, and a second gate conductive layer 84 may be sequentially formed. The gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be formed of the same materials as described with reference to FIGS. 8LA to 8LD by the same processes as described with reference to FIGS. 8LA to 8LD.

As shown in FIGS. 13DA to 13DD, the gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be planarized by, for example, a CMP process. Thus, a first gate 90 a including a first gate dielectric layer 80 a and a first gate electrode 88 a may be formed on the first fin subregion 20 a, a second gate 90 b including a second gate dielectric layer 80 b and a second gate electrode 88 b may be formed on the second fin subregion 20 b, and a third gate 90 c including a third gate dielectric layer 80 c and a third gate electrode 88 c may be formed on the second isolation insulating layer 60. Each of the first to third gate electrodes 88 a, 88 b and 88 c may include the first gate conductive layer 82 and the second gate conductive layer 84. A height of the third gate 90 c disposed on the second isolation insulating layer 60 may be substantially equal to heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. Alternatively, the height of the third gate 90 c disposed on the second isolation insulating layer 60 may be smaller than the heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. On the other hand, a height of the third gate 90 c disposed on the first isolation insulating layer 24 may be smaller than heights of the first and second gates 90 a, 90 b disposed on the first isolation insulating layer 24. For example, on the first isolation insulating layer 24, the height of the third gate 90 c may be smaller than the heights of the first and second gates 90 a, 90 b by a height of the filling insulation layer 66. The filling insulation layer 66 may extend in the second direction Y, and the third gate 90 c may extend on the filling insulation layer 66 in the second direction Y. In some embodiments, if the filling insulation layer 66 is a discrete isolation insulating island, the third gate 90 c may cover sidewalls and a top surface of the second isolation insulating layer 60 and may extend in the second direction Y to intersect the first isolation insulating layer 24.

FIGS. 14AA to 14CD are cross-sectional views illustrating some processes of a method of manufacturing the semiconductor device according to the fifth embodiment of the inventive concepts. FIGS. 14AA to 14CA are cross-sectional views taken along a line A-A′ of FIG. 5, and FIGS. 14AB to 14CB are cross-sectional views taken along a line B-B′ of FIG. 5. FIGS. 14AC to 14CC are cross-sectional views taken along a line C-C′ of FIG. 5, and FIGS. 14AD to 14CD are cross-sectional views taken along a line D-D′ of FIG. 5. Hereinafter, the descriptions of elements already described above with respect to FIGS. 8AA to 8MD will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiment of FIGS. 8AA to 8MD may be highlighted.

As shown in FIGS. 14AA to 14AD, a second isolation insulating layer 60 according to the present embodiment may have a height smaller than that of the filling insulation layer 66 described with reference to FIGS. 13BA to 13BD. For example, the filling insulation layer 66 illustrated in FIGS. 13AA to 13AD may be etched back to expose a portion of the second recess region 53, so the sidewalls of the oxide layer 64 may be partially exposed. A top surface of the filling insulation layer 66 may be lower than the top surfaces of the first and second fin subregions 20 a, 20 b.

As shown in FIGS. 14BA to 14BD, the first and second sacrificial gates 30 a, 30 b and the sacrificial gate dielectric layers 28 are selectively removed. Thereafter, a gate dielectric layer 80, a first gate conductive layer 82, and a second gate conductive layer 84 may be sequentially formed. The gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be formed of the same materials as described with reference to FIGS. 8LA to 8LD by the same processes as described with reference to FIGS. 8LA to 8LD.

As shown in FIGS. 14CA to 14CD, the gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be planarized by, for example, a CMP process. Thus, a first gate 90 a including a first gate dielectric layer 80 a and a first gate electrode 88 a may be formed on the first fin subregion 20 a, a second gate 90 b including a second gate dielectric layer 80 b and a second gate electrode 88 b may be formed on the second fin subregion 20 b, and a third gate 90 c including a third gate dielectric layer 80 c and a third gate electrode 88 c may be formed on the second isolation insulating layer 60. Each of the first to third gate electrodes 88 a, 88 b and 88 c may include the first gate conductive layer 82 and the second gate conductive layer 84. A height of the third gate 90 c disposed on the second isolation insulating layer 60 may be greater than the heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. For example, a bottom surface of the third gate 90 c disposed on the filling insulation layer 66 of the second isolation insulating layer 60 may be lower than the top surfaces of the first and second fin subregions 20 a, 20 b. On the other hand, a height of the third gate 90 c disposed on the first isolation insulating layer 24 may be smaller than heights of the first and second gates 90 a, 90 b disposed on the first isolation insulating layer 24. For example, on the first isolation insulating layer 24, the height of the third gate 90 c may be smaller than the heights of the first and second gates 90 a, 90 b by a height of the filling insulation layer 66. The filling insulation layer 66 may extend in the second direction Y, and the third gate 90 c may extend on the filling insulation layer 66 in the second direction Y. In some embodiments, if the filling insulation layer 66 is a discrete isolation insulating island, the third gate 90 c may cover sidewalls and a top surface of the second isolation insulating layer 60 and may extend in the second direction Y to intersect the first isolation insulating layer 24.

FIG. 15A is a plan view illustrating a semiconductor device according to a sixth embodiment of the inventive concepts. FIGS. 15B, 15C, 15D, and 15E are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 15A, respectively.

As shown in FIGS. 15A to 15E, a semiconductor device according to a sixth embodiment of the inventive concepts may include fin regions 20, a first gate 90 a, a second gate 90 b, and a third gate 90 c, a first isolation insulating layer 12, and a second isolation insulating layer 60, and first and second source/drain regions 40 a, 40 b.

Each of the fin regions 20 may extend in a first direction (e.g., an X-axis direction) and may include a first fin subregion 20 a and a second fin subregion 20 b which are isolated from each other. The fin regions 20 may be provided on the first isolation insulating layer 12. The fin regions 20 may be separated from each other in a second direction (e.g., a Y-axis direction) different from the first direction X. Bottom surfaces of the fin regions 20 may be in contact with a top surface of the first isolation insulating layer 12. The first direction X and the second direction Y may intersect each other. For example, the first direction X and the second direction Y may be perpendicular to each other. However, the inventive concepts are not limited thereto. The fin regions 20 may be patterns that include a semiconductor material and are formed on the first isolation insulating layer 12. FIGS. 15A to 15E illustrate two fin regions 20 separated from each other in the second direction Y as an example. However, the inventive concepts are not limited thereto.

A substrate may be a semiconductor-on-insulator (SOI) substrate. The substrate may include a lower semiconductor layer 10, the first isolation insulating layer 12, and an upper semiconductor layer. The upper semiconductor layer may be patterned to form a plurality of fin regions 20 on the first isolation insulating layer 12. The lower semiconductor layer 10 may include at least one semiconductor material selected from a group consisting of silicon (Si), germanium (Ge), silicon-germanium (SiGe), gallium-phosphorus (GaP), gallium-arsenic (GaAs), silicon-carbon (SiC), silicon-germanium-carbon (SiGeC), indium-arsenic (InAs), or indium-phosphorus (InP). The fin regions 20 formed from the upper semiconductor layer may include at least one semiconductor material selected from a group consisting of silicon (Si), germanium (Ge), silicon-germanium (SiGe), gallium-phosphorus (GaP), gallium-arsenic (GaAs), silicon-carbon (SiC), silicon-germanium-carbon (SiGeC), indium-arsenic (InAs), or indium-phosphorus (InP). The first isolation insulating layer 12 may be a buried oxide layer. The first isolation insulating layer 12 may be formed using, for example, a separation by implanted oxygen (SIMOX) method, or an oxidation method, or a deposition method.

Each of the fin regions 20 may have a length and a width. The first direction X may be parallel to a length direction of each of the fin regions 20, and the second direction Y may be parallel to a width direction of each of the fin regions 20. One end of the first fin subregion 20 a may face one end of the second fin subregion 20 b in the first direction X.

The first and second fin subregions 20 a, 20 b may be used as active regions and channel regions of fin field effect transistors (FINFETs). For example, an N-type transistor (e.g., an NMOS transistor) or a P-type transistor (e.g., PMOS transistor) may be formed on the first fin subregion 20 a and/or the second fin subregion 20 b. For example, a first transistor 110 may be formed on the first fin subregion 20 a, and a second transistor 120 may be formed on the second fin subregion 20 b. The first transistor 110 may include a first gate 90 a and first source/drain regions 40 a. The second transistor 120 may include a second gate 90 b and second source/drain regions 40 b.

The second isolation insulating layer 60 may be disposed between the first fin subregion 20 a and the second fin subregion 20 b to isolate the first fin subregion 20 a from the second fin subregion 20 b in the first direction X. The first transistor 110 and the second transistor 120 may be isolated from each other by the second isolation insulating layer 60. The second isolation insulating layer 60 may be a discrete isolation insulating island (e.g., an island-shaped pattern) and may be provided in plurality. For example, a plurality of second isolation insulating layers 60 may be spaced apart from each other in the second direction Y to be aligned with each other. The second isolation insulating layer 60 may be an oxide layer formed by oxidizing a portion of the fin region 20. For example, the portion of the fin region 20 provided on the first isolation insulating layer 12 may be oxidized to self-alignedly form the second isolation insulating layer 60. A top surface of the second isolation insulating layer 60 may be curved. A bottom surface of the second isolation insulating layer 60 may be substantially coplanar with the top surface of the first isolation insulating layer 12. The top surface of the isolation insulating layer 60 may be substantially coplanar with or lower than top surfaces of the first and second fin subregions 20 a, 20 b.

Sidewalls of the second isolation insulating layer 60 may be in contact with a sidewall of the first fin subregion 20 a and a sidewall of the second fin subregion 20 b, respectively. A width in the second direction Y of the second isolation insulating layer 60 may be substantially equal to widths in the second direction Y of the first and second fin subregions 20 a, 20 b. However, the inventive concepts are not limited thereto. In other embodiments, the width in the second direction Y of the second isolation insulating layer 60 may be less or greater than the widths in the second direction Y of the first and second fin subregions 20 a, 20 b.

The first gate 90 a crossing over the first fin subregion 20 a and the second gate 90 b crossing over the second fin subregion 20 b may extend in the second direction Y. The first gate 90 a may cover sidewalls and a top surface of the first fin subregion 20 a thereunder and may extend in the second direction Y to intersect the first isolation insulating layer 12. The second gate 90 b may cover sidewalls and a top surface of the second fin subregion 20 b thereunder and may extend in the second direction Y to intersect the first isolation insulating layer 12. The third gate 90 c may cover sidewalls and a top surface of the second isolation insulating layer 60 and may extend in the second direction Y to cross the first isolation insulating layer 12. For example, the third gate 90 c may cover the sidewalls and the top surface of the second isolation insulating layer 60 exposed between gate spacers 34 adjacent to both sidewalls of the third gate 90 c and may extend in the second direction Y to cross the first isolation insulating layer 12. The first and second gates 90 a, 90 b may be uses as normal gates for operating transistors, but the third gate 90 c may be used as a dummy gate which is not used for operating a transistor. Alternatively, the third gate 90 c may be used as an interconnection for transmitting a signal or a normal gate. A width of the third gate 90 c may be substantially equal to or smaller than widths of the first and second gates 90 a, 90 b. FIGS. 15A and 15B illustrate a single third gate 90 c disposed on a single second isolation insulating layer 60 as an example. However, the inventive concepts are not limited thereto. In other embodiments, two or more third gates 90 c may be disposed on a single second isolation insulating layer 60.

The first gate 90 a may include a first gate electrode 88 a and a first gate dielectric layer 80 a. The second gate 90 b may include a second gate electrode 88 b and a second gate dielectric layer 80 b. The third gate 90 c may include a third gate electrode 88 c and a third gate dielectric layer 80 c.

The first and second gate dielectric layers 80 a, 80 b may be disposed between the first and second fin subregions 20 a, 20 b and the first and second gate electrodes 88 a and 88 b, respectively. In addition, the third gate dielectric layer 80 c may be disposed between the third gate electrode 88 c and the second isolation insulating layer 60. Each of the gate dielectric layers 80 a, 80 b, 80 c may surround sidewalls and a bottom surface of a corresponding one of the first to third gate electrodes 88 a, 88 b, 88 c and may extend in the second direction Y. Each of the first and second gate dielectric layers 80 a, 80 b may cover the sidewalls and the top surface of the corresponding one of the first and second fin subregions 20 a, 20 b together with each of the first and second gate electrodes 80 a, 88 b and may extend in the second direction Y. The third gate dielectric layer 80 c may cover the sidewalls and the top surface of the second isolation insulating layer 60 together with the third gate electrode 88 c and may extend in the second direction Y. The gate dielectric layers 80 a, 80 b, 80 c may intersect the first isolation insulating layer 12 and may extend in the second direction Y. Each of the gate dielectric layers 80 a, 80 b, 80 c may include a high-k dielectric material having a dielectric constant higher than that of silicon oxide. For example, Each of the gate dielectric layers 80 a, 80 b, 80 c may include at least one of, but not limited to, hafnium oxide (e.g., HfO₂), hafnium-silicon oxide, lanthanum oxide (e.g., La₂O₃), lanthanum-aluminum oxide, zirconium oxide (e.g., ZrO₂), zirconium-silicon oxide, tantalum oxide (e.g., Ta₂O₅), titanium oxide, barium-strontium-titanium oxide, barium-titanium oxide, strontium-titanium oxide, yttrium oxide, aluminum oxide (e.g., Al₂O₃), lead-scandium-tantalum oxide, or lead-zinc niobate.

A width of a lower portion of the third gate electrode 88 c may be smaller than a width of an upper portion of the second isolation insulating layer 60. A top surface of the first gate electrode 88 a, a top surface of the second gate electrode 88 b, and a top surface of the third gate electrode 88 c may be substantially coplanar with each other. For example, the top surfaces of the gate electrodes 88 a, 88 b, 88 c may be in the same plane through a planarization process. Top surfaces of the gate dielectric layers 80 a, 80 b, 80 c may also be substantially coplanar with the top surfaces of the gate electrodes 88 a, 88 b, 88 c, respectively. Heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b may be substantially equal to a height of the third gate 90 c disposed on the second isolation insulating layer 60. For example, heights of the first and second gate electrodes 88 a and 88 b disposed on the first and second fin subregions 20 a, 20 b may be substantially equal to a height of the third gate electrode 88 c disposed on the second isolation insulating layer 60. Accordingly, if the third gate electrode 88 c is used as a signal interconnection or a normal gate electrode, the third gate electrode 88 c has the same thickness as other gate electrodes 88 a, 88 b to reduce/prevent a signal delay phenomenon through the third gate electrode 88 c. As a result, characteristics of the semiconductor device according to the inventive concepts may be improved. Alternatively, the heights of the first and second gate electrodes 88 a and 88 b disposed on the first and second fin subregions 20 a, 20 b may be greater than the height of the third gate electrode 88 c disposed on the second isolation insulating layer 60.

Each of the first and second gate electrodes 88 a and 88 b may include a first gate conductive layer 82 and a second gate conductive layer 84. The first gate conductive layer 82 may be disposed between the second gate conductive layer 84 and the first and second gate dielectric layers 80 a, 80 b to control a work function of a corresponding one of the first and second gate electrodes 88 a, 88 b. The second gate conductive layer 84 may fill a space formed by the first gate conductive layer 82. The first gate conductive layer 82 may include a metal. For example, the first gate conductive layer 82 may include at least one of titanium nitride (TiN), tantalum nitride (TaN), titanium carbide (TiC), titanium-aluminum (TiAl), titanium-aluminum carbide (TiAlC), titanium-aluminum nitride (TiAlN), tantalum carbide (TaC), or tantalum-aluminum nitride (TaAlN). The second gate conductive layer 84 may include a metal. For example, the second conductive layer 84 may include tungsten (W) or aluminum (Al). The third gate electrode 88 c may include a first gate conductive layer 82 and a second gate conductive layer 84. The first gate conductive layer 82 of the third gate electrode 88 c may be disposed between the third gate dielectric layer 80 c and the second gate conductive layer 84, and the second gate conductive layer 84 of the third gate electrode 88 c may fill a space formed by the first gate conductive layer 82 of the third gate electrode 88 c. The first and second gate conductive layers 82, 84 of the third gate electrode 88 c may be formed of the same materials as the first and second gate conductive layers 82, 84 of each of the first and second gate electrodes 88 a, 88 b, respectively. The first to third gate electrodes 88 a, 88 b, 88 c may be formed by a replacement process or a gate last process. However, the inventive concepts are not limited thereto.

Gate spacers 34 may be formed to be adjacent to both sidewalls of each of the first to third gates 90 a, 90 b, 90 c. The gate spacers 34 may extend in the second direction Y together with the first to third gates 90 a, 90 b, 90 c. The gate dielectric layers 80 a, 80 b, 80 c may extend to be disposed between the gate spacer 34 and each of the gate electrodes 88 a, 88 b, 88 c. Top surfaces of the gate spacers 34 may be planarized to be substantially coplanar with the top surfaces of the gate electrodes 88 a, 88 b, 88 c. The sidewalls of the second isolation insulating layer 60 which are parallel to the second direction Y may be substantially aligned with inner sidewalls of the gate spacers 34 adjacent to the both sidewalls of the third gate electrode 88 c, or the top surface of the second isolation insulating layer 60 may overlap with and be in contact with portions of bottom surfaces of the gate spacers 34. The gate spacer 34 may include silicon nitride and/or silicon oxynitride.

The source/drain regions 40 a, 40 b including dopants may be disposed to be adjacent to the sidewalls of the first to third gates 90 a, 90 b, 90 c. For example, the first source/drain regions 40 a may be formed in the first fin subregion 20 a adjacent to the both sidewalls of the first gate 90 a, and the second source/drain regions 40 b may be formed in the second fin subregion 20 b adjacent to the both sidewalls of the second gate 90 b. The first and second source/drain regions 40 a, 40 b may include an epitaxial layer including a semiconductor material. For example, the epitaxial layer including the semiconductor material may be formed in each of first recess regions 36 formed in the first fin subregion 20 a and the second fin subregion 20 b. In addition, the first and second source/drain regions 40 a, 40 b may protrude to be higher than the top surfaces of the first and second fin subregions 20 a, 20 b, so the first and second source/drain regions 40 a, 40 b may have elevated source/drain structures. A cross section of each of the first and second source/drain regions 40 a, 40 b may have a polygonal shape, an elliptical shape, or a circular shape. In some embodiments, at least one of the first and second source/drain regions 20 a, 20 b may not include the epitaxial layer. The first gate electrode 88 a and the first source/drain region 40 a may be isolated from each other by the gate spacer 34. In addition, the second gate electrode 88 b and the second source/drain region 40 b may be isolated from each other by the gate spacer 34. The third gate electrode 88 c may be spaced apart from the first and second source/drain regions 40 a, 40 b by the gate spacer 34 and the second isolation insulating layer 60 self-alignedly formed, so a short and a leakage current between the third gate electrode 88 c and the source/drain regions 40 a, 40 b may be impeded/prevented.

If the first transistor 110 and/or the second transistor 120 are the PMOS transistor, the first source/drain region 40 a and/or the second source/drain region 40 b may include a compressive stress material. The compressive stress material may be a material (e.g., SiGe) having a lattice constant greater than that of silicon. The compressive stress material may apply a compressive stress to the first fin subregion 20 a under the first gate electrode 88 a and/or the second fin subregion 20 b under the second gate electrode 88 b, thereby improving mobility of carries of a channel region.

If the first transistor 110 and/or the second transistor 120 are the NMOS transistor, the first source/drain region 40 a and/or the second source/drain region 40 b may include the same material as the fin regions 20 or a tensile stress material. For example, if the fin regions 20 are formed of silicon, the first source/drain region 40 a and/or the second source/drain region 40 b may include silicon or a material (e.g., SiC) having a lattice constant smaller than that of silicon.

A silicide layer 42 may be formed on each of the first and second source/drain regions 40 a, 40 b. The silicide layer 42 may include a metal. For example, the silicide layer 42 may include at least one of nickel (Ni), cobalt (Co), platinum (Pt), or titanium (Ti).

An interlayer insulating layer 44 may be formed on the silicide layer 42. The interlayer insulating layer 44 may partially fill a gap between the gate spacers 34. The interlayer insulating layer 44 may include silicon oxide or a low-k dielectric material having a dielectric constant lower than that of silicon oxide. The interlayer insulating layer 44 may include a porous insulating material. Meanwhile, an air gap may be formed in the interlayer insulating layer 44. Protection patterns 46 may be formed on the interlayer insulating layer 44. Top surfaces of the protection patterns 46 may be substantially coplanar with the top surfaces of the gate electrodes 88 a, 88 b, 88 c. The protection patterns 46 may include a nitride and/or an oxynitride.

FIG. 16A is a plan view illustrating a semiconductor device according to a seventh embodiment of the inventive concepts. FIGS. 16B, 16C, 16D, and 16E are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 16A, respectively. Hereinafter, the descriptions of elements already described above with respect to FIGS. 15A to 15E will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiment of 15A to 15E may be highlighted.

As shown in FIGS. 16A to 16E, a semiconductor device according to a seventh embodiment of the inventive concepts may include a second isolation insulating layer 60 having a pair of insulating layers separated from each other. The second isolation insulating layer 60 may be in contact with the sidewalls of the first and second fin subregions 20 a, 20 b. For example, the second isolation insulating layer 60 may include oxide layers that are self-alignedly formed on the sidewall of the first fin subregion 20 a and the sidewall of the second fin subregion 20 b which face each other in the first direction X. For example, sidewalls of the fin region 20 exposed by a second recess region 53 formed in the fin region 20 may be self-alignedly oxidized to form the oxide layers of the second isolation insulating layer 60. For example, the sidewalls of the first and second fin subregions 20 a, 20 b exposed by the second recess region 53 may be selectively oxidized to form the second isolation insulating layer 60. A bottom surface of the second isolation insulating layer 60 may be in contact with the top surface of the first isolation insulating layer 12. A third gate 90 c may cover inner sidewalls of the second isolation insulating layer 60 and may extend in the second direction Y. A portion of the third gate 90 c may fill the second recess region 53. For example, portions of the third gate electrode 88 c and the third gate dielectric layer 80 c of the third gate 90 c may be disposed between the inner sidewalls of the second isolation insulating layer 60 and may extend in the second direction Y.

The third gate 90 c may extend on the first isolation insulating layer 12 in the second direction Y with a substantially uniform height. The third gate 90 c may extend from the top surface of the gate spacer 34 to the top surface of the first isolation insulating layer 12, and sidewalls of the third gate 90 c may be in contact with the gate spacers 34 and the second isolation insulating layer 60 under the gate spacers 34. A height of the third gate 90 c at a position where the third gate 90 c is in contact with the second isolation insulating layer 60 may be greater than the heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. Heights of the first to third gates 90 a, 90 b, 90 c disposed on the first isolation insulating layer 12 between the fin regions 20 may be substantially equal to each other.

FIG. 17A is a plan view illustrating a semiconductor device according to an eighth embodiment of the inventive concepts. FIGS. 17B, 17C, 17D, and 17E are cross-sectional views taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 17A, respectively. Hereinafter, the descriptions of elements already described above with respect to FIGS. 15A to 15E and 16A to 16E will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiments of 15A to 15E and 16A to 16E may be highlighted.

As shown in FIGS. 17A to 17E, a semiconductor device according to an eighth embodiment of the inventive concepts may include may include a second isolation insulating layer 60 including an oxide layer 64 and a filling insulation layer 66. The oxide layer 64 may have the same structure and the same material as the second isolation insulating layer 60 described with reference to FIGS. 16A to 16E. The filling insulation layer 66 may fill the second recess region 53 having sidewalls on which the oxide layers 64 are formed. A top surface of the filling insulation layer 66 may be substantially coplanar with the top surfaces of the first and second fin subregions 20 a, 20 b. Alternatively, the top surface of the filling insulation layer 66 may be higher than the top surfaces of the first and second fin subregions 20 a, 20 b.

The filling insulation layer 66 may be in contact with the first isolation insulating layer 12 and may extend in the second direction Y. A height of the third gate 90 c may be smaller than heights of the first and second gates 90 a, 90 b on the first isolation insulating layer 12 between the fin regions 20. The third gate 90 c may extend on the second isolation insulating layer 60 in the second direction Y. In some embodiments, the filling insulation layer 66 may be a discrete isolation insulating island (e.g., an island-shaped pattern) like the second isolation insulating layer 60 illustrated in FIG. 15A. In this case, the third gate 90 c may cover a top surface and sidewalls of at least the filling insulation layer 66 of the second isolation insulating layer 60 and may extend in the second direction Y to intersect the first isolation insulating layer 12.

In some embodiments, the filling insulation layer 66 may have a top surface lower than top surfaces of the oxide layers 64 and the top surfaces of the first and second fin subregions 20 a, 20 b, as described with reference to FIGS. 7A to 7D. In this case, the filling insulation layer 66 may be a linear pattern extending in the second direction Y or a discrete isolation insulating island. Like the third gate 90 c described with reference to FIGS. 7A to 7D, a height of the third gate 90 c disposed on the second isolation insulating layer 60 may be greater than the heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. On the other hand, on the first isolation insulating layer 12 between the fin regions 20, a height of the third gate 90 c may be smaller than heights of the first and second gates 90 a, 90 b by a height of the filling insulation layer 66. The third gate 90 c may extend on the second isolation insulating layer 60 in the second direction Y. Meanwhile, if the filling insulation layer 66 is a discrete isolation insulating island, the third gate 90 c may cover a top surface and sidewalls of at least the filling insulation layer 66 of the second isolation insulating layer 60 and may extend in the second direction Y to cross the first isolation insulating layer 12.

FIGS. 18AA to 18LD are cross-sectional views illustrating some processes of a method of manufacturing the semiconductor device according to the sixth embodiment of the inventive concepts. FIGS. 18AA to 18LA are cross-sectional views taken along a line A-A′ of FIG. 15A, and FIGS. 18AB to 18LB are cross-sectional views taken along a line B-B′ of FIG. 15A. FIGS. 18AC to 18LC are cross-sectional views taken along a line C-C′ of FIG. 15A, and FIGS. 18AD to 18LD are cross-sectional views taken along a line D-D′ of FIG. 15A.

As shown in FIGS. 18AA to 18AD, a semiconductor-on-insulator (SOI) substrate may be provided. The SOI substrate may include a lower semiconductor layer 10, a first isolation insulating layer 12, and an upper semiconductor layer 14 which are sequentially stacked. The lower and upper semiconductor layers 10 and 14 may include at least one semiconductor material selected from a group consisting of, for example, Si, Ge, SiGe, GaP, GaAs, SiC, SiGeC, InAs, or InP. The first isolation insulating layer 12 may be a buried oxide layer. The first isolation insulating layer 12 may be formed using, for example, a separation by implanted oxygen (SIMOX) method, or an oxidation method, or a deposition method.

As shown in FIGS. 18BA to 18BD, the upper semiconductor layer 14 may be patterned to form fin regions 20 that extend in a first direction X and are spaced apart from each other in a second direction Y. The fin regions 20 may be isolated from each other in the second direction Y by the first isolation insulating layer 12. The first direction X may cross the second direction Y. For example, the first direction X may be perpendicular to the second direction Y. However, the inventive concepts are not limited thereto. Each of the fin regions 20 may be formed to have a linear shape and may have a length and a width. A length direction of each of the fin regions 20 may be parallel to the first direction X, and a width direction of each of the fin regions 20 may be parallel to the second direction Y.

Sacrificial gates 30 a, 30 b, 30 c may be formed to cross the fin regions 20 along the second direction Y. For example, a first sacrificial gate 30 a and a second sacrificial gate 30 b may be disposed to be parallel to each other with a third sacrificial gate 30 c therebetween. The first to third sacrificial gates 30 a, 30 b, 30 c may extend in the second direction Y. The sacrificial gates 30 a, 30 b, 30 c may cover a top surface and sidewalls of each of the fin regions 20 and may extend in the second direction Y to intersect the first isolation insulating layer 12. The first to third sacrificial gates 30 a, 30 b, 30 c may include, for example, a poly-silicon layer or an amorphous silicon layer. A sacrificial gate dielectric layer 28 may be formed between each of the fin regions 20 and each of the sacrificial gates 30 a, 30 b, 30 c. The sacrificial gate dielectric layer 28 may include, for example, a thermal oxide layer. A gate capping layer 32 may be formed on a top surface of each of the first to third sacrificial gates 30 a, 30 b, 30 c. Gate spacers 34 may be formed on sidewalls of each of the first to third sacrificial gates 30 a, 30 b, 30 c and sidewalls of the gate capping layer 32. The gate spacers 34 may extend in parallel with the first to third sacrificial gates 30 a, 30 b, 30 c in the second direction Y. The gate capping layer 32 and the gate spacer 34 may include silicon nitride and/or silicon oxynitride.

As shown in FIGS. 18CA to 18CD, portions of the fin regions 20 adjacent to the gate spacers 34 may be etched using the gate capping layers 32 and the gate spacers as an etch mask to form first recess regions 36. For example, the first recess regions 36 may be formed using a dry etching method or using a dry etching method and a wet etching method. Bottom surfaces of the first recess regions 36 may be disposed in the fin regions 20. Inner sidewalls of the first recess regions 36 may be aligned with sidewalls of the gate spacers 34. In some embodiments, the first recess regions 36 may be enlarged to partially expose bottom surfaces of the gate spacers 34.

As shown in FIGS. 18DA to 18DD, an epitaxial layer 38 may be formed in each of the first recess regions 36. The epitaxial layer 38 may be formed by selectively epitaxial-growing a semiconductor material. If a PMOS transistor is formed, the epitaxial layer 38 may be formed by epitaxial-growing a compressive stress material. The compressive stress material may have a lattice constant greater than that of silicon. For example, silicon-germanium (SiGe) may be epitaxial-grown to form a SiGe epitaxial layer. Alternatively, if an NMOS transistor is formed, the epitaxial layer 38 may be formed by epitaxial-growing the same material as the fin regions 20 or a tensile stress material. For example, if the fin regions 20 are formed of silicon (Si), silicon (Si) or silicon carbide (SiC) may be epitaxial-grown to form a Si epitaxial layer or a SiC epitaxial layer having a lattice constant smaller than that of silicon. A top surface of the epitaxial layer 38 may be formed to be higher than the top surface of the fin region 20. A cross section of the epitaxial layer 38 may have a polygonal shape, a circular shape, or an elliptical shape.

As shown in FIGS. 18EA to 18ED, the epitaxial layers 38 may be doped with dopants to form first and second source/drain regions 40 a, 40 b. The first source/drain regions 40 a may be formed to be adjacent to sidewalls of the first sacrificial gate 30 a, and the second source/drain regions 40 b may be formed to be adjacent to sidewalls of the second sacrificial gate 30 b. In some embodiments, the epitaxial layers 38 may be doped with P-type or N-type dopants in-situ to form the first and second source/drain regions 40 a, 40 b when the epitaxial layers 38 are formed. In other embodiments, the first and second source/drain regions 40 a, 40 b may be formed by ion-implanting P-type or N-type dopants into the epitaxial layers 38. The first and second drain regions 40 a, 40 b may be formed in the epitaxial layers 38 to have elevated source/drain structures. In some embodiments, if the epitaxial layer 38 is not formed, dopants may be injected into the fin region 20 to form the first and/or second source/drain regions 40 a and/or 40 b.

The first and second source/drain regions 40 a, 40 b may be isolated from the first to third sacrificial gates 30 a, 30 b, 30 c by the gate spacers 34. A silicide layer 42 may be formed on each of the first and second source/drain regions 40 a, 40 b. The silicide layer 42 may include at least one metal of nickel (Ni), cobalt (Co), platinum (Pt), or titanium (Ti). An interlayer insulating layer 44 may be formed on the silicide layers 42. The interlayer insulating layer 44 may include an oxide or a low-k dielectric material. The interlayer insulating layer 44 may include a porous material. The interlayer insulating layer 44 may include an air gap therein. The interlayer insulating layer 44 may be formed using a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, or a spin coating process. The interlayer insulating layer 55 may be formed to cover the gate capping layers 32 and may be etched back until the gate capping layer 32 and portions of the gate spacers 34 are exposed. The interlayer insulating layer 44 may partially fill a space between the gate spacers 34 facing each other. A protection layer 46 a may be formed on the interlayer insulating layer 44. The protection layer 46 a may be formed to cover the gate capping layer 32 and the gate spacer 34 which are exposed by the interlayer insulating layer 44. For example, the protection layer 46 a may include a nitride and/or an oxynitride.

As shown in FIGS. 18FA to 18FD, protection patterns 46 may be formed on the interlayer insulating layer 44 to be spaced apart from each other. For example, the protection layer 46 a and the gate capping layer 32 may be planarized by, for example, a chemical mechanical polishing (CMP) process, so the gate capping layer 32 and a portion of the protection layer 46 a thereon may be removed to form the protection patterns 46. At this time, the gate spacer 34 may be partially removed. As a result, top surfaces of the first to third sacrificial gates 30 a, 30 b, 30 c may be exposed.

As shown in FIGS. 18GA to 18GD, a first mask 50 may be formed to cover the first and second sacrificial gates 30 a, 30 b and to have a first opening 51 exposing the third sacrificial gate 30 c. The first opening 51 may have a width greater than the width of the third sacrificial gate 30 c in the first direction X and may extend in the second direction Y. The first opening 51 may partially expose the gate spacers 34 and the protection patterns 46 which are adjacent to the third sacrificial gate 30 c. The first mask 50 may include a hard mask layer or a photoresist layer. The hard mask layer may be formed of, for example, a spin-on-hardmask (SOH) layer. The third sacrificial gate 30 c and the sacrificial gate dielectric layer 28 may be removed using the first mask 50 as an etch mask to form a first groove 52. The first and second source/drain regions 40 a, 40 b adjacent to the third sacrificial gate 30 c are covered with the gate spacers 34 and the protection patterns 46 during the formation of the first groove 52 not to be exposed, and thus, it is possible to protect/prevent the first and second source/drain regions 40 a, 40 b from being etched. The first groove 52 may expose portions of the fin regions 20. In addition, the first groove 52 may partially expose the first isolation insulating layer 12.

As shown in FIGS. 18HA to 18HD, the fin regions 20 exposed by the first groove 52 may be trimmed to form trimmed fin regions 23. For example, a portion of the fin region 20 may be removed through the trimming process by, for example, a thickness S. Each of the top surface and the sidewalls of the fin region 20 may be removed by the thickness S. For example, the thickness S may be in a range of 1/20 to ⅓ of the width of each of the fin regions 20.

As shown in FIGS. 18IA to 18ID, the first mask 50 may be removed, and the trimmed fin region 23 may be then oxidized to form a second isolation insulating layer 60. The second isolation insulating layer 60 may be formed to be self-aligned with the first groove 52 by the oxidation of the trimmed fin region 23 exposed by the first groove 52. For example, the second isolation insulating layer 60 may be an oxide layer that is formed by oxidizing the trimmed fin region 23 using a plasma oxidation process. For example, the trimmed fin region 23 may be oxidized using an oxygen gas or an ozone gas at a temperature of 20° C. to 800° C. under a plasma atmosphere to form the second isolation insulating layer 60. In other embodiments, the second isolation insulating layer 60 may be an oxide layer that is formed by oxidizing the trimmed fin region 23 using a thermal oxidation process. For example, the second isolation insulating layer 60 may be an oxide layer which is formed by oxidizing the trimmed fin region 23 using a dry oxidation process, a wet oxidation process, or a thermal radical oxidation process. Alternatively, the second isolation insulating layer may be formed by the SIMOX process described with reference to FIGS. 9AA to 9AD. A first fin subregion 20 a and a second fin subregion 20 b separated from each other in the first direction X may be formed in each of the fin regions 20 by the second isolation insulating layer 60. The second isolation insulating layer 60 may be in contact with the first isolation insulating layer 12.

The second isolation insulating layer 60 may be a discrete isolation insulating island (e.g., an island-shaped pattern) having a top surface and sidewalls. For example, sidewalls of the second isolation insulating layer 60 which are arranged in the second direction Y may be exposed by the first groove 52. In other words, the sidewalls of the second isolation insulating layer 60 exposed by the first groove 52 may be parallel to the first direction X. Sidewalls of the second isolation insulating layer 60 which are arranged in the first direction X may be in contact with the sidewall of the first fin subregion 20 a and the sidewall of the second fin subregion 20 b which face each other. In other words, the sidewalls of the second isolation insulating layer 60 which are in contact with the sidewalls of the first and second fin subregions 20 a, 20 b may be parallel to the second direction Y. A plurality of the second isolation insulating layers 60 may be spaced apart from and aligned with each other in the second direction Y. In some embodiments, the sidewalls of the second isolation insulating layer 60 arranged in the first direction X may be in contact with the first and second source/drain regions 40 a, 40 b. The second isolation insulating layer 60 may have sidewalls aligned with inner sidewalls of the gate spacers 34. Alternatively, a width in the first direction X of the second isolation insulating layer 60 may be widened, so a top surface of the second isolation insulating layer 60 may partially overlap with a bottom surface of the gate spacer 34. In some embodiments, the trimming process of the fin regions 20 may be omitted and the fin regions 20 may be oxidized to form the second isolation insulating layers 60.

As shown in FIGS. 18JA to 18JD, a second groove 62 may be formed on each of the first and second fin subregions 20 a, 20 b. For example, the second grooves 62 may formed by sequentially removing the first and second sacrificial gates 30 a, 30 b and the sacrificial gate dielectric layer 28. For example, the first and second sacrificial gates 30 a, 30 b may be selectively removed using the gate spacers 34 and the protection patterns 46 as an etch mask. When the sacrificial gate dielectric layer 28 is removed, a portion of the second isolation insulating layer 60 may be removed. Top surfaces and sidewalls of the first and second fin subregions 20 a, 20 b may be partially exposed by the second grooves 62. In addition, portions of the first isolation insulating layer 12 may be exposed by the second grooves 62.

As shown in FIGS. 18KA to 18KD, a gate dielectric layer 80, a first gate conductive layer 82, and a second gate conductive layer 84 may be sequentially formed to fill the first and second grooves 52 and 62. The gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be formed by a replacement process refilling spaces formed by the removal of the sacrificial gates 30 a, 30 b, 30 c. The gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may cover the top surfaces and the sidewalls of the first and second fin subregions 20 a, 20 b. In addition, the gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may cover the top surface and the sidewalls of the second isolation insulating layer 60. The gate dielectric layer 80 may include a high-k dielectric material having a dielectric constant higher than that of silicon oxide. For example, the gate dielectric layer 80 may include at least one of, but not limited to, hafnium oxide, hafnium-silicon oxide, lanthanum oxide, lanthanum-aluminum oxide, zirconium oxide, zirconium-silicon oxide, tantalum oxide, titanium oxide, barium-strontium-titanium oxide, barium-titanium oxide, strontium-titanium oxide, yttrium oxide, aluminum oxide, lead-scandium-tantalum oxide, or lead-zinc niobate.

The gate dielectric layer 80 may be formed using an ALD process or a CVD process. The first gate conductive layer 82 may include a material capable of controlling a work function of a gate electrode. The second gate conductive layer 84 may fill spaces defined by the first gate conductive layer 82. The first gate conductive layer 82 may include a metal. For example, the first gate conductive layer 82 may include at least one of titanium nitride (TiN), tantalum nitride (TaN), titanium carbide (TiC), titanium-aluminum (TiAl), titanium-aluminum carbide (TiAlC), titanium-aluminum nitride (TiAlN), tantalum carbide (TaC), or tantalum-aluminum nitride (TaAlN). The second gate conductive layer 84 may include a metal. For example, the second conductive layer 84 may include tungsten (W) or aluminum (Al). Each of the first and second gate conductive layers 82 and 84 may be formed using an ALD process or a CVD process.

As shown in FIGS. 18LA to 18LD, a first gate 90 a may be formed on the first fin subregion 20 a, a second gate 90 b may be formed on the second fin subregion 20 b, and a third gate 90 c may be formed on the second isolation insulating layer 60. The first gate 90 a may include a first gate dielectric layer 80 a and a first gate electrode 88 a, the second gate 90 b may include a second gate dielectric layer 80 b and a second gate electrode 88 b, and the third gate 90 c may include a third gate dielectric layer 80 c and a third gate electrode 88 c. To form the first to third gates 90 a, 90 b and 90 c, the second gate conductive layer 84, the first gate conductive layer 82, and the gate dielectric layer 80 may be planarized by, for example, a CMP method until the protection patterns 46 and the gate spacers 34 are exposed. Thus, the gate dielectric layer 80 and the first and second gate conductive layers 82 and 84 may be removed from top surfaces of the protection patterns 46 and the gate spacers 34 but may remain in the first and second grooves 52 and 62. As a result, the first gate electrode 88 a may be formed to include the first and second gate conductive layers 82 and 84 intersecting the first fin subregion 20 a, and the second gate electrode 88 b may be formed to include the first and second gate conductive layers 82, 84 intersecting the second fin subregion 20 b. In addition, the third gate electrode 88 c may be formed to include the first and second conductive layers 82, 84 intersecting the second isolation insulating layer 60. The first gate dielectric layer 80 a may be disposed between the first fin subregion 20 a and the first gate electrode 88 a, the second gate dielectric layer 80 b may be disposed between the second fin subregion 20 b and the second gate electrode 88 b, and the third gate dielectric layer 80 c may be disposed between the second isolation insulating layer 60 and the third gate electrode 88 c. Each of the gate dielectric layers 80 a, 80 b, 80 c may surround sidewalls and a bottom surface of a corresponding one of the first to third gate electrodes 88 a, 88 b, 88 c and may extend in the second direction Y. The first and second gate electrodes 88 a, 88 b and the first and second gate dielectric layers 80 a, 80 b may cover the top surfaces and the sidewalls of the first and second fin subregions 20 a, 20 b, respectively, and may extend in the second direction Y. The third gate electrode 88 c and the third gate dielectric layer 80 c may surround the top surface and the sidewalls of the second isolation insulating layer 60 and may extend in the second direction Y. Accordingly, the first and second gates 90 a, 90 b respectively intersecting the first and second fin subregions 20 a, 20 b may extend in the second direction Y. The first gate 90 a may cover the top surface and the sidewalls of the first fin subregion 20 a and may extend in the second direction Y to intersect the first isolation insulating layer 12. The second gate 90 b may cover the top surface and the sidewalls of the second fin subregion 20 b and may extend in the second direction Y to intersect the first isolation insulating layer 12. The third gate 90 c may cover the top surface and the sidewalls of the second isolation insulating layer 60 and may extend in the second direction Y to intersect the first isolation insulating layer 12. For example, the third gate 90 c may cover the sidewalls and the top surface of the second isolation insulating layer 60 which are exposed between the gate spacers 34 adjacent to the sidewalls of the third gate 90 c and may extend in the second direction Y to intersect the first isolation insulating layer 12.

The first and second gates 90 a, 90 b may be used as normal gates for operation of transistors, but the third gate 90 c may be used as a dummy gate that is not used for operation of a transistor. Alternatively, the third gate 90 c may be used as a signal-transmitting interconnection or a normal gate.

A width of the third gate 90 c may be substantially equal to or smaller than widths of the first and second gates 90 a, 90 b. Heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b may be substantially equal to a height of the third gate 90 c disposed on the second isolation insulating layer 60. For example, heights of the first and second gate electrodes 88 a, 88 b disposed on the first and second fin subregions 20 a, 20 b may be substantially equal to a height of the third gate electrode 88 c disposed on the second isolation insulating layer 60. Accordingly, if the third gate electrode 88 c is used as a signal-transmitting interconnection or a normal gate electrode, the third gate electrode 88 c has the same thickness as other gate electrodes 88 a, 88 b to reduce/prevent a signal delay phenomenon through the third gate electrode 88 c. As a result, characteristics of the semiconductor device according to the inventive concepts may be improved.

A first transistor 110 including the first gate 90 a and the first source/drain regions 40 a may be formed on the first fin subregion 20 a, and a second transistor 120 including the second gate 90 b and the second source/drain regions 40 b may be formed on the second fin subregion 20 b. The first transistor 110 and/or the second transistor 120 may be an N-type transistor and/or a P-type transistor. The second isolation insulating layer 60 may isolate the first transistor 110 from the second transistor 120. For example, the first transistor 110 may be electrically and physically isolated from the second transistor 120 by the second isolation insulating layer 60. An isolation characteristic between the first and second transistors 110, 120 may be improved by the second isolation insulating layer 60 and the first isolation insulating layer 12 disposed under the first isolation insulating layer 60.

FIGS. 19AA to 19DD are cross-sectional views illustrating some processes of a method of manufacturing the semiconductor device according to the seventh embodiment of the inventive concepts. FIGS. 19AA to 19DA are cross-sectional views taken along a line A-A′ of FIG. 16A, and FIGS. 19AB to 19DB are cross-sectional views taken along a line B-B′ of FIG. 16A. FIGS. 19AC to 19DC are cross-sectional views taken along a line C-C′ of FIG. 16A, and FIGS. 19AD to 19DD are cross-sectional views taken along a line D-D′ of FIG. 16A. Hereinafter, the descriptions of elements already described above with respect to FIGS. 18AA to 18LD will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiment of 18AA to 18LD may be highlighted.

As shown in FIGS. 19AA to 19AD, a portion of each of the fin regions 20 exposed by the first groove 52 may be removed using the first mask 50 as an etch mask to form a second recess region 53. For example, the fin region 20 exposed by the first groove region 52 may be removed to form the second recess region 53. The first isolation insulating layer 12 may be exposed by the second recess region 53. A portion of the first isolation insulating layer 12 may also be removed during the formation of the second recess region 53.

As shown in FIGS. 19BA to 19BD, after the first mask 50 is removed, the fin region 20 exposed by the second recess region 53 may be oxidized to form a second isolation insulating layer 60. The second isolation insulating layer 60 may be an oxide layer self-alignedly formed on sidewalls of the second recess region 53. The second isolation insulating layer 60 may include a pair of oxide layers separated from each other. Portions of the fin region 20 exposed by the second recess region 53 may be oxidized by a plasma oxidation process to form the second isolation insulating layer 60. For example, the fin region 20 exposed by the second recess region 53 may be oxidized using an oxygen gas or an ozone gas at a temperature of 20° C. to 800° C. under a plasma atmosphere to form the second isolation insulating layer 60. In other embodiments, the fin region 20 exposed through the second recess region 53 may be oxidized by a thermal oxidation process to form the second isolation insulating layer 60. For example, the thermal oxidation process may be a dry oxidation process, a wet oxidation process, or a thermal radical oxidation process. Alternatively, the second isolation insulating layer 60 may be formed by the SIMOX method described with reference to FIGS. 9AA to 9AD. The second isolation insulating layer 60 may be insulating layers formed on only both sidewalls of the second recess region 53. A top surface of the second isolation insulating layer 60 may partially overlap with the gate spacer 34, and the second isolation insulating layer 60 may protrude into the second recess region 53. Thus, a width of an opened region (e.g., a distance between the pair of oxide layers) of the second recess region 53 may be smaller than the width of the first groove 52 in the first direction X. In some embodiments, the second isolation insulating layer 60 may be in contact with the first and second source/drain regions 40 a, 40 b. A first fin subregion 20 a and a second fin subregion 20 b may be isolated from each other by the second isolation insulating layer 60.

As shown in FIGS. 19CA to 19CD, the first and second sacrificial gates 30 a, 30 b and the sacrificial gate dielectric layers 28 may be selectively removed to form second grooves 62. A gate dielectric layer 80, a first gate conductive layer 82, and a second gate conductive layer 84 may be sequentially formed on the substrate 10 to fill the first groove 52 and the second grooves 62. The gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be formed of the same materials as described with reference to FIGS. 18KA to 18KD by the same processes as described with reference to FIGS. 18KA to 18KD.

As shown in FIGS. 19DA to 19DD, the gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be planarized by, for example, a CMP process. Thus, a first gate 90 a including a first gate dielectric layer 80 a and a first gate electrode 88 a may be formed on the first fin subregion 20 a, a second gate 90 b including a second gate dielectric layer 80 b and a second gate electrode 88 b may be formed on the second fin subregion 20 b, and a third gate 90 c including a third gate dielectric layer 80 c and a third gate electrode 88 c may be formed on the second isolation insulating layer 60. Each of the first to third gate electrodes 88 a, 88 b, 88 c may include the first gate conductive layer 82 and the second gate conductive layer 84. The third gate 90 c may extend on the first isolation insulating layer 12 in the second direction Y with a uniform height. The third gate 90 c may extend from the top surface of the gate spacer 34 to the top surface of the first isolation insulating layer 12. A height of the third gate 90 c at a position where the third gate 90 c is in contact with the second isolation insulating layer 60 may be greater than the heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. Heights of the first to third gates 90 a, 90 b, 90 c disposed on the first isolation insulating layer 12 between the fin regions 20 may be substantially equal to each other.

FIGS. 20AA to 20CD are cross-sectional view illustrating some processes of a method of manufacturing the semiconductor device according to the eighth embodiment of the inventive concepts. FIGS. 20AA to 20CA are cross-sectional views taken along a line A-A′ of FIG. 17A, and FIGS. 20AB to 20CB are cross-sectional views taken along a line A-A′ of FIG. 17A. FIGS. 20AC to 20CC are cross-sectional views taken along a line A-A′ of FIG. 17A, and FIGS. 20AD to 20CD are cross-sectional views taken along a line A-A′ of FIG. 17A. Hereinafter, the descriptions of elements already described above with respect to FIGS. 18AA to 18LD will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiments of 18AA to 18LD and 19AA to 19DD may be highlighted.

As shown in FIGS. 20AA to 20AD, the fin region 20 exposed by the sidewalls of the second recess region 53 may be oxidized to form an oxide layer 64. The oxide layer 64 may be formed by, for example, the same process as the formation process of the second isolation insulating layer 60 described with reference to FIGS. 19BA to 19BD. A filling insulation layer 66 may be formed to fill the first groove 52 having the oxide layer 64 and the second recess region 53. For example, the filling insulation layer 66 may include an oxide and/or a nitride.

As shown in FIGS. 20BA to 20BD, the filling insulation layer 66 may be recessed to expose the first groove 52. For example, a blanket etch-back process may be performed to remove a portion of the filling insulation layer 66 formed on the protection patterns 46 and the sacrificial gates 30 a, 30 b and another portion of the filling insulation layer 66 formed in the first groove 52. For example, the portions of the filling insulation layer 66 may be selectively removed with respect to the protection patterns 46 and the sacrificial gates 30 a, 30 b. Thus, a second isolation insulating layer 60 may be formed to include the oxide layer 64 and the filling insulation layer 66 which fill the second recess region 53. In some embodiments, a top surface of the filling insulation layer 66 formed in the second recess region 53 may be a little higher than the top surfaces of the first and second fin subregions 20 a, 20 b. For example, the top surface of the filling insulation layer 66 may be substantially coplanar with a top surface of the sacrificial gate dielectric layer 28. Alternatively, the top surface of the filling insulation layer 66 may be formed to be higher than the top surface of the sacrificial gate dielectric layer 28.

The filling insulation layer 66 may have a structure extending in the second direction Y. The filling insulation layer 66 may be formed on the first isolation insulating layer 12. In some embodiments, the filling insulation layer 66 may be formed to be a discrete isolation insulating island (e.g., an island-shaped pattern). In this case, a plurality of filling insulation layers 66 formed under the first groove 52 may be spaced apart from each other in the second direction Y. Thus, the filling insulation layer 66 and the oxide layer 64 self-alignedly formed may have an isolated shape like the second isolation insulating layer 60 illustrated in FIG. 15A.

As shown in FIGS. 20CA to 20CD, the first and second sacrificial gates 30 a, 30 b and the sacrificial gate dielectric layers 28 are selectively removed. A portion of the filling insulation layer 66 may be removed during the removal of the sacrificial gate dielectric layers 28, so a top surface of the filling insulation layer 66 may be substantially coplanar with, for example, the top surfaces of the first and second fin subregions 20 a, 20 b. Alternatively, the top surface of the filling insulation layer 66 may be higher than the top surfaces of the first and second fin subregions 20 a, 20 b.

Thereafter, a gate dielectric layer 80, a first gate conductive layer 82, and a second gate conductive layer 84 may be sequentially formed. The gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be formed of the same materials as described with reference to FIGS. 18KA to 18KD by the same processes as described with reference to FIGS. 18KA to 18KD. Subsequently, the gate dielectric layer 80, the first gate conductive layer 82, and the second gate conductive layer 84 may be planarized by, for example, a CMP process. Thus, a first gate 90 a including a first gate dielectric layer 80 a and a first gate electrode 88 a may be formed on the first fin subregion 20 a, a second gate 90 b including a second gate dielectric layer 80 b and a second gate electrode 88 b may be formed on the second fin subregion 20 b, and a third gate 90 c including a third gate dielectric layer 80 c and a third gate electrode 88 c may be formed on the second isolation insulating layer 60. Each of the first to third gate electrodes 88 a, 88 b, 88 c may include the first gate conductive layer 82 and the second gate conductive layer 84. A height of the third gate 90 c disposed on the second isolation insulating layer 60 may be substantially equal to heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. Alternatively, the height of the third gate 90 c disposed on the second isolation insulating layer 60 may be smaller than the heights of the first and second gates 90 a, 90 b disposed on the first and second fin subregions 20 a, 20 b. On the first isolation insulating layer 12 between the fin regions 20, a height of the third gate 90 c may be smaller than heights of the first and second gates 90 a, 90 b. For example, the height of the third gate 90 c may be smaller than the heights of the first and second gates 90 a, 90 b by a height of the filling insulation layer 66 on the first isolation insulating layer 12 between the fin regions 20. The filling insulation layer 66 may extend in the second direction Y, and the third gate 90 c may extend on the filling insulation layer 66 in the second direction Y. In some embodiments, if the filling insulation layer 66 is the discrete isolation insulating island, the third gate 90 c may cover sidewalls and a top surface of the second isolation insulating layer 60 and may extend in the second direction Y.

FIGS. 21A to 21D are cross-sectional views respectively taken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 17A to illustrate a process of another embodiment of a method of manufacturing the semiconductor device according to the eighth embodiment of the inventive concepts. Hereinafter, the descriptions of elements already described above with respect to FIGS. 18AA to 18LD will be omitted or mentioned only briefly so that differences between the present embodiment and the embodiments of 18AA to 18LD, 19AA to 19DD and 20AA to 20CD may be highlighted.

As shown in FIGS. 21A to 21D, a second isolation insulating layer 60 may include a filling insulation layer 66 having a height lower than the height of the filling insulation layer 66 illustrated in FIGS. 20CA to 20CD. For example, the filling insulation layer 66 illustrated in FIGS. 20AA to 20AD may further be etched back to expose a portion of the second recess region 53, so a portion of the oxide layer 64 may be exposed. A top surface of the filling insulation layer 66 may be lower than the top surfaces of the first and second fin subregions 20 a, 20 b. Thereafter, the first and second sacrificial gates 30 a, 30 b may be removed and then processes of forming a gate dielectric layer and gate electrodes may be performed as described with reference to FIGS. 20BA to 20CD.

FIG. 22 is a schematic block diagram illustrating an example of electronic systems including semiconductor devices according to embodiments of the inventive concepts. The semiconductor devices described with reference to FIGS. 1 to 21D may be applied to an electronic system of FIG. 22.

As shown in FIG. 22, an electronic system 1000 according to embodiments of the inventive concepts may include a controller 1100, an input/output unit 1200, a memory device 1300, an interface unit 1400, and a data bus 1500. The controller 1100, the input/output unit 1200, the memory device 1300, and/or the interface unit 1400 may be coupled to each other through the data bus 1500. The data bus 1500 may correspond to a path through which data are transmitted.

The controller 1100 may include at least one of a microprocessor, a digital signal processor, a microcontroller, or other logic devices capable of performing a similar function to any one thereof. The input/output unit 1200 may include a keypad, a keyboard and/or a display unit. The memory device 1300 may store data and/or commands. The interface unit 1400 may transmit electrical data to a communication network or may receive electrical data from a communication network. The interface unit 1400 may operate by wireless or cable. For example, the interface unit 1400 may include an antenna a wireless/cable transceiver. The electronic system 1000 may further include a fast dynamic random access memory (DRAM) device and/or a fast static random access memory (SRAM) device which acts as a cache memory for improving an operation of the controller 1100. The semiconductor devices according to embodiments of the inventive concepts may be provided to the controller 1100, the cache memory of the controller 1100, and/or the input/output unit 1200.

The electronic system 1000 may be applied to a personal digital assistant (PDA), a portable computer, a web tablet, a wireless phone, a mobile phone, a digital music player, a memory card, or other electronic products receiving and/or transmitting information data by wireless.

In the semiconductor device according to embodiments of the inventive concepts, the gate electrode is disposed on the isolation insulating layer which is self-alignedly formed. Thus, it is possible to protect against (e.g., impede/prevent) the short or leakage current between the source/drain region formed in the fin region and the gate electrode disposed on the isolation insulating layer. As a result, reliability of the semiconductor device may be improved.

While the inventive concepts have been described with reference to example embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirits and scopes of the inventive concepts. Therefore, it should be understood that the above embodiments are not limiting, but illustrative. Thus, the scope of the inventive concepts is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing description. 

What is claimed is:
 1. A method of manufacturing a semiconductor device, the method comprising: forming a fin region protruding from a substrate and extending in a first direction, the fin region comprising opposing sidewalls that extend in the first direction; forming an isolation insulating layer on the opposing sidewalls of the fin region, the isolation insulating layer exposing upper portions of the opposing sidewalls of the fin region; after forming the isolation insulating layer, forming a discrete isolation insulating island in the fin region by oxidizing a portion of the fin region, thereby forming a first fin subregion and a second fin subregion separated from each other in the first direction by the discrete isolation insulating island, the isolation insulating layer exposing an upper portion of the discrete isolation insulating island; and forming a gate extending on the discrete isolation insulating island in a second direction different from the first direction.
 2. The method of claim 1, wherein oxidizing the portion of the fin region comprises performing a plasma oxidation process or a thermal oxidation process.
 3. The method of claim 1, wherein oxidizing the portion of the fin region comprises implanting oxygen ions into the portion of the fin region and thermally treating the fin region.
 4. The method of claim 1, wherein the portion of the fin region comprises a first portion of the fin region, and wherein the method further comprises injecting dopants into a second portion of the fin region underneath the discrete isolation insulating island to form a punch-through stop layer.
 5. The method of claim 1, wherein forming the gate comprises forming a first gate, a second gate and a third gate that extend in the second direction, and wherein the first gate traverses the first fin subregion, the second gate traverses the second fin subregion, and the third gate extends on the discrete isolation insulating island.
 6. The method of claim 5, wherein oxidizing the portion of the fin region comprises: forming a sacrificial gate dielectric layer on the fin region; forming a first sacrificial gate and a second sacrificial gate spaced apart from each other on the sacrificial gate dielectric layer, the first and second sacrificial gates intersecting the fin region in the second direction; forming a third sacrificial gate on the sacrificial gate dielectric layer, the third sacrificial gate intersecting the fin region between the first and second sacrificial gates in the second direction; forming a gate spacer on a sidewall of each of the first, second and third sacrificial gates; removing the third sacrificial gate and a portion of the sacrificial gate dielectric layer disposed under the third sacrificial gate to form a first groove exposing the portion of the fin region; and oxidizing the portion of the fin region exposed by the first groove.
 7. The method of claim 6, wherein forming the first, second and third gates comprises: removing the first sacrificial gate, the second sacrificial gate, and portions of the sacrificial gate dielectric layer disposed under the first and second sacrificial gates to form second grooves on the first and second fin subregions; and forming a gate dielectric layer and a gate electrode in each of the first and second grooves to form the first gate and the second gate in respectively ones of the second grooves, and to form the third gate in the first groove, wherein each of the first, second and third gates comprises the gate dielectric layer and the gate electrode.
 8. The method of claim 5, wherein oxidizing the portion of the fin region comprises: forming a sacrificial gate dielectric layer on the fin region; forming a first sacrificial gate and a second sacrificial gate spaced apart from each other on the sacrificial gate dielectric layer, the first and second sacrificial gates intersecting the fin region in the second direction; forming a third sacrificial gate on the sacrificial gate dielectric layer, the third sacrificial gate intersecting the fin region between the first and second sacrificial gates in the second direction; forming a gate spacer on a sidewall of each of the first, second and third sacrificial gates; removing the third sacrificial gate and a portion of the sacrificial gate dielectric layer disposed under the third sacrificial gate to form a first groove exposing the portion of the fin region; trimming the portion of the fin region exposed by the first groove; and oxidizing the trimmed portion of the fin region exposed by the first groove.
 9. The method of claim 5, wherein oxidizing the portion of the fin region comprises: forming a sacrificial gate dielectric layer on the fin region; forming a first sacrificial gate and a second sacrificial gate spaced apart from each other on the sacrificial gate dielectric layer, the first and second sacrificial gates intersecting the fin region in the second direction; forming a third sacrificial gate on the sacrificial gate dielectric layer, the third sacrificial gate intersecting the fin region between the first and second sacrificial gates in the second direction; forming a gate spacer on a sidewall of each of the first, second and third sacrificial gates; removing the third sacrificial gate and a portion of the sacrificial gate dielectric layer disposed under the third sacrificial gate to form a first groove exposing the portion of the fin region; removing the portion of the fin region exposed by the first groove to form a recess region; and oxidizing surfaces of the recess region.
 10. The method of claim 9, wherein the discrete isolation insulating island comprises an oxide layer having a U-shaped cross section.
 11. The method of claim 9, wherein the discrete isolation insulating island comprises a pair of oxide layers separated from each other in the first direction.
 12. The method of claim 1, wherein the gate is on opposing sidewalls of the upper portion of the discrete isolation insulating island.
 13. A method of manufacturing a semiconductor device, the method comprising: forming a fin region protruding from a surface of a substrate, the fin region comprising a first fin subregion and a second fin subregion spaced apart from each other in a first direction; forming a first isolation insulating layer being in contact with sidewalls of the first and second fin subregions, which extend in the first direction, the first isolation insulating layer extending in the first direction; forming a discrete isolation insulating island disposed between the first fin subregion and the second fin subregion, the discrete isolation insulating island separating the first fin subregion from the second fin subregion and comprising a lower surface facing the fin region, and the lower surface of the discrete isolation insulating island being at a level between a level of the surface of the substrate and a level of an upper surface of the first fin subregion; forming a first gate intersecting the first fin subregion and extending in a second direction different from the first direction; forming a second gate intersecting the second fin subregion and extending in the second direction; and forming a third gate on a top surface and opposing sidewalls of the discrete isolation insulating island and extending in the second direction, wherein each of the first to third gates comprises a gate dielectric layer and a gate electrode, wherein the third gate intersects the first isolation insulating layer, and wherein a bottom surface of the third gate disposed on the first isolation insulating layer is lower than a top surface of the first isolation insulating layer.
 14. The method of claim 13, further comprising: forming first source/drain regions in the first fin subregion adjacent to sidewalls of the first gate, the first source/drain regions comprising one or more dopants of a first conductivity type; and forming second source/drain regions in the second fin subregion adjacent to sidewalls of the second gate, the second source/drain regions comprising dopants of the first conductivity type.
 15. The method of claim 14, wherein the fin region further comprises a third fin subregion that is disposed underneath the discrete isolation insulating island, and wherein the method further comprises forming a punch-through stop layer in the third fin subregion, the punch-through stop layer comprising dopants having a second conductivity type different from the first conductivity type.
 16. The method of claim 14, wherein at least one of the first and second source/drain regions includes an epitaxial layer.
 17. The method of claim 13, wherein the opposing sidewalls of the discrete isolation insulating island are parallel to the first direction and exposed by the fin region.
 18. A method of manufacturing a semiconductor device, the method comprising: forming a fin region extending in a first direction on a substrate; forming gate spacers on the fin region, the gate spacers extending in a second direction different from the first direction and defining a groove that exposes a portion of the fin region; forming a recess region in the fin region by removing the portion of the fin region exposed by the groove; oxidizing surfaces of the recess region to form an oxide layer; forming a filling insulation layer filling the recess region on the oxide layer to form an isolation insulating layer comprising the oxide layer and the filling insulation layer; and forming a gate filling the groove on the filling insulation layer, the gate including a gate dielectric layer and a gate electrode.
 19. The method of claim 18, further comprising: forming a punch-through stop layer including dopants in the fin region underneath the isolation insulating layer. 